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I have quite a few older bikes that have the classic XC geometry - steep head tube, narrow bars, long stem.

For my kind of trail riding, I much prefer the geometry of a more modern trail bike.

I used to ride one of my older bikes with a high angle stem and risers to bring the bars up and reduce endoing... but now that I'm used to more modern geometry, I'm starting to think that was the wrong approach - you don't want to raise the bars on these older bikes too much, or you end up with a light front end that corners and climbs badly, and it's still not a great descender.

What do you do? Can you go short on the stem? How short? Wide bars? I think putting a full modern stem and bars on an old bike doesn't work right. Do you?
 

· furker
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What do you do? Can you go short on the stem? How short? Wide bars? I think putting a full modern stem and bars on an old bike doesn't work right. Do you?
All the modern stuff has to go together or it doesn't work. You can't pick and choose. The best I've been able to do is make minor changes around the edges or it ruins the bike. Too much bar/stem change, and you run into problems with the short frame reach, steep head angle, seat position, etc.

You start changes in one place, and eventually you end up with some part of the bike you can't change that ruins everything and leaves you worse than before. You end up with no choice but to start rolling back the changes.

Change the bar and stem, and you realize the fork and head angle have to change. Longer fork and steeper head angle, now the seat has to come forward too far and the bottom bracket is too high, and the bike is unstable. Exactly the opposite of the stability that comes with modern geometry (while now suffering from steering flop too). And your body position is too far forwards and the bike wants to toss you over the bars. Forward body position only works if your bottom bracket is low enough compared to your axles and far enough back behind your front axle. (think "drop your heels" and not ever being able to drop them far enough)

Eventually sanity prevails and you are really lucky if you can get away with 10-20mm shorter stem, 60-80mm wider bars, and 10-20mm longer fork than you started with. And that's only if the bike had a low bottom bracket and decent reach to start with.

Best case you have a reasonably better blue/green trail bike that doesn't feel too weird when swapping back and forth between it and a modern bike.
 

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All the modern stuff has to go together or it doesn't work. You can't pick and choose.

...

Eventually sanity prevails and you are really lucky if you can get away with 10-20mm shorter stem, 60-80mm wider bars, and 10-20mm longer fork than you started with. And that's only if the bike had a low bottom bracket and decent reach to start with.
I have a much more positive take on this than you, but it depends on your starting point. On my particular bike which I've had since new in '93 (Stumpjumper FS hardtail), I was too low and stretched out in the early years. The changes that improve an old bike (raising the front with fork, bringing hands up in cockpit) shorten the reach, so the end result is way better balanced than the original set up. If your starting point wasn't too long like mine was, you have less room to improve the bike. I've basically optimized what the bare vintage geometry frame can do with regards to fit with my body. The resulting position allows me to be a lot more capable on this bike than it was in the '90s and '00s. Also, the bottom bracket was too low to begin with, and even with the longer fork, sits lower than modern hardtails with more fork travel. I think the bottom bracket height is now perfect for the amount of travel the fork I'm using has (65mm Marzocchi Z2 Bomber). It's a fully capable and fun ride for old school XC trails (what 90% of mountain bikers actually ride vs. the more hardcore that mtbr and pinkbike attracts).

One part that you can absolutely pick and choose is the bar width. I've been browsing the retrobike (UK) forum lately. I can understand the retro builds having narrow bars, but it puzzles me that the "retro mod" builds also have narrow-ish bars. Once I got away from the narrow bars, I kept going up by feel on both the old bike and a 29er hardtail to where my hands wanted to land naturally, and ended up in the sweet spot that modern cross country riders use (surveying a ton of bike checks of World Cup bikes... between 700mm and 760mm). That's a body position that makes you stable on the bike through corners, as well as give you extra leverage compared to narrow bars to hold your line when terrain is torqueing on the front wheel. I see "modern" bar width as the single best upgrade on a vintage mountain bike ridden on trails. There's no reason it has to be matched to a certain stem length on an old bike.

On my '94 Stumpjumper FS, I've gone up about 25-30mm in fork axle to crown, down 20mm in stem length, up 180mm in bar width, up 80-90mm in saddle to bar drop (to about level with saddle, which is perfect for XC with my slightly negative ape index/shorter arms), and forward in saddle about 20-30mm (despite longer fork, with help of switching from setback to straight seatpost).

If I were to get a custom modern hardtail bike (which I'm not, because this old bike is just right for where and how I ride), I'd put the touch points in the exact same position as I have on the '93 bike now, with only geometry changes to lengthen reach/shorten stem, increase seat angle so saddle sits in middle of the rails, and slacken the head tube a degree or so (currently at around 69.5 from 71 original). I wouldn't go super slack as I'd not be after a Kona Honzo type bike, but an XC hardtail.

I realize that making all these changes might not make sense to an old bike. In my case, I had plenty of ~$5 stems and bars to play around with/optimize fit and $8 forks from the local co-op. The result is so good that I've doubled down on tweaking the '93 bike rather than replace my much more recent 29er XC hardtail (carbon XX1 cranks, 1x11 XT, XT discs, carbon Roval wheels, carbon bars) that was stolen last year.

At this point, because of my style of riding, I don't want anything more. I'm out to enjoy nature with my dog(s), ride for fitness and fun, ride tech uphills, play/practice wheelies and manuals, etc, but not ride increasingly gnarly downhills.
 

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I'm starting to think that was the wrong approach - you don't want to raise the bars on these older bikes too much, or you end up with a light front end that corners and climbs badly, and it's still not a great descender.

What do you do? Can you go short on the stem? How short? Wide bars? I think putting a full modern stem and bars on an old bike doesn't work right. Do you?
Just talking about my particular old bike with improvements I did mostly in fit, my front end is not light with the higher bars. With a stem that is still 11cm long (from original 13cm), and a steeper head angle than modern trail hardtails (69.5degrees, less than original 71), I have considerably more weight in front than a slack modern bike. Enough so that I went with the same tires front and rear (Race Kings) instead of gripper in front like the current trend. The front still doesn't go out first.

Originally, my bike was sketchy as heck on downhills. I put half the blame on the stretched out position which leaves little for body position adjustments. I had a stretched out, flat back position like a roadie with a large saddle to bar drop (80-90mm with the stem as high as possible). Horizontal position of the bars being close relative to the front wheel, mainly due to long and low stem, and steep head tube angle would be next to blame. Narrow bars were also to blame because you didn't have a strong bracing position. Raising the bars/longer fork improved the body position, slacked out the head tube 1.5 degrees, and shorter stem (though still considered long these days) were enough to improve the downhill ability from sketchy to fun. I'd say the downhill rating went from maybe 1/5 to 4/5 for what you'd run on a XC hardtail with 65mm travel. There's no point comparing with a modern slack trail hardtail, unless that's what you're looking for.

Like I said in my previous post, go with modern bar width, but use the stem to get the right fit for how upright you want to be, even if it has to be longer than what is currently fashionable.
 

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I was too low and stretched out in the early years. The changes that improve an old bike (raising the front with fork, bringing hands up in cockpit) shorten the reach, so the end result is way better balanced than the original set up. If your starting point wasn't too long like mine was, you have less room to improve the bike.
Expanding on this a bit more, if your body position looked like Tomac on your original set up of your vintage bike, you have room to update it with a longer fork, and higher hand position to make it ride a lot better than before. You'll end up looking more the positions in the bottom photos after the changes.

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If your body position on your vintage bike is already more upright, like Richards or Pidcock, you have less room to improve the bike because you don't want to make make the reach shorter. You can put a wider bar on it though.

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· furker
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I have a much more positive take on this than you, but it depends on your starting point. On my particular bike which I've had since new in '93 (Stumpjumper FS hardtail), I was too low and stretched out in the early years. The changes that improve an old bike (raising the front with fork, bringing hands up in cockpit) shorten the reach, so the end result is way better balanced than the original set up. I've basically optimized what the bare vintage geometry frame can do with regards to fit with my body, and the resulting position allows me to be a lot more capable on this bike than it was in the '90s and '00s. Also, the bottom bracket was too low to begin with, and even with the longer fork, sits lower than modern hardtails with more fork travel. I think the bottom bracket height is now perfect for the amount of travel the fork I'm using has (65mm Marzocchi Z2 Bomber). It's a fully capable and fun ride for old school XC trails (what 90% of mountain bikers actually ride vs. the more hardcore that mtbr and pinkbike attracts).

One part that you can absolutely pick and choose is the bar width. I've been browsing the retrobike (UK) forum lately. I can understand the retro builds having narrow bars, but it puzzles me that the "retro mod" builds also have narrow-ish bars. Once I got away from the narrow bars, I kept going up by feel on both the old bike and a 29er hardtail to where my hands wanted to land naturally, and ended up in the sweet spot that modern cross country riders use (surveying a ton of bike checks of World Cup bikes... between 700mm and 760mm). That's a body position that makes you stable on the bike through corners, as well as give you extra leverage compared to narrow bars to hold your line when terrain is torqueing on the front wheel. I see "modern" bar width as the single best upgrade on a vintage mountain bike ridden on trails. There's no reason it has to be matched to a certain stem length on an old bike.

On my '94 Stumpjumper FS, I've gone up about 25-30mm in fork axle to crown, down 20mm in stem length, up 180mm in bar width, up 80-90mm in saddle to bar drop (to about level with saddle, which is perfect for XC with my slightly negative ape index/shorter arms), and forward in saddle about 20-30mm (despite longer fork, with help of switching from setback to straight seatpost).

If I were to get a custom modern hardtail bike (which I'm not, because this old bike is just right for where and how I ride), I'd put the touch points in the exact same position as I have on the '93 bike now, with only geometry changes to lengthen reach/shorten stem, increase seat angle so saddle sits in middle of the rails, and slacken the head tube a degree or so (currently at around 69.5 from 71 original). I wouldn't go super slack as I'd not be after a Kona Honzo type bike, but an XC hardtail.

I realize that making all these changes might not make sense to an old bike. In my case, I had plenty of ~$5 stems and bars to play around with/optimize fit and $8 forks from the local co-op. The result is so good that I've doubled down on tweaking the '93 bike rather than replace my much more recent 29er XC hardtail (carbon XX1 cranks, 1x11 XT, XT discs, carbon Roval wheels, carbon bars) that was stolen last year.

At this point, because of my style of riding, I don't want anything more. I'm out to enjoy nature with my dog(s), ride for fitness and fun, ride tech uphills, play/practice wheelies and manuals, etc, but not ride increasingly gnarly downhills.
Yea, your starting point is about a decade older than I was thinking when I responded to the OP's question about 00's bikes (where I was envisioning typical mid-00's 120mm stems of that time).

Your choice of bars makes sense from your starting point. The original stem was probably around 130-150mm, and was way too long compared to even the 00's bikes. And even narrower bars than typical 00's bikes. Your big change in bar width effectively solves for those abnormally long stems and even narrower bars. It also matches up with your bomber fork rake, which has less rake than the rigid forks put on early StumpJumpers that all the Specialized bike cockpits were designed around (they didn't change the cockpit for suspension fork bikes). Shorter fork rake dictates shorter reach, and the wider bars achieve that.

I agree that I would not ride the increasingly gnarly downhills on that bike either, but it would do fine on blue/green type of trails.

The early StumpJumpers are so radically different than the newer ones that they almost aren't for the same sport anymore. Check out the fork rake, and the stem length before super long stems became trendy:


 

· gbnemba.org
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I still ride my 2005 Kona Dawg Deelux as my only full suspension and have adapted it as geometry has progressed over the years.

When I got my first 29er (Jamis Exile) I moved the wider (660 mm) risers with 31.8 clamp onto it for better control and stiffer front end. I also shed the big ring.

years passed and I rotated in a niner emd, adjusting stem height a bit on that bike to make swaps more natural. I also ran 1x9 on the 29ers which was so much nicer.

then I got a 2017 Salsa Mukluk with “modern geo” and fell in love. It became my four season bike, I sold the niner and used the proceeds on a Bluto. I was less enchanted with the Dawg - it felt less stable on descents than the Mukluk - but then also wanted something for very techy terrain.

it hit me to try the Mukluk bars on the Dawg. 2 inches wider made a BIG difference and I feel more stable on bumps and at speed. It put COG a little more forward for corners and climbing too.

the last step was drivetrain. I finally removed the front derailleur, putting 26t Absolute Black up front with 11-36 out back. Same lowest ratio as my 11spd Mukluk and I don’t miss the top end (never used anything above the middle of cassette on trail). Less thinking about shifting and easier to react quickly to sudden elevation changes.

l’ll see if I can get 20 years out of it - just a few more to go and new bikes are crazy $$$ these days.
 

· Cycologist
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That's got a dropbar on it and he's in the drops, not really a fair comparison. And what's going on with the chain!? And disk on rear wheel! :D

Looks like a REALLY early gravel race.
 

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I have quite a few older bikes that have the classic XC geometry - steep head tube, narrow bars, long stem.

For my kind of trail riding, I much prefer the geometry of a more modern trail bike.

I used to ride one of my older bikes with a high angle stem and risers to bring the bars up and reduce endoing... but now that I'm used to more modern geometry, I'm starting to think that was the wrong approach - you don't want to raise the bars on these older bikes too much, or you end up with a light front end that corners and climbs badly, and it's still not a great descender.

What do you do? Can you go short on the stem? How short? Wide bars? I think putting a full modern stem and bars on an old bike doesn't work right. Do you?
I think you can tell by these responses that it really depends on what specific bike you have now, and how it fits you.

Without getting into the weeds, finding the right combination of stem spacers, stem length, bar width (rise and sweep), fork A2C (travel) and angled headsets can transform how an older bike fits and rides.

Just the small step on my 2010 Redline d440 of changing from a 100mm, 12* stem and 670, 20mm rise bar to a 70mm, 6* stem and 760, 30mm rise bar really made a difference in how the bike rode. Had I wanted to take it further, I would have definitely consider a longer A2C fork in combination with an angle set. But, just because that might work for me on that specific bike doesn't mean similar changes would work for you on your specific bike.
 

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A bike frame is a collection of tubes and angles, it's pretty simple. The internet is just a series of tubes ;)

Seriously, in my opinion the best use for an old-school geometry is to consider it to be a smaller-sized bike. A 2002 Large is equivalent to a modern Medium or Small. Do this, giving it to a smaller rider (wifey bike), and your short stem and wide bars will work with it.

Adding a longer-travel fork to an old bike will slacken the head angle, but be warned it'll also shorten the already short reach. It'll also slacken the already slack seat tube angle.

One thing to understand is that wider bars will effectively lower the rider position in a better, more controlled way than long stem, short bars will.

I'd use the RAD measurement as your guide to whether these modifications are effective for you.

 

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What do you do? Can you go short on the stem? How short? Wide bars? I think putting a full modern stem and bars on an old bike doesn't work right. Do you?
Yeah, all these things. I did a (non-budget) restomod on a 1998 FSR this summer. I think it rides really good, but then I have low expectations and only have flat land experience on the modern geometry to compare to. Of these changes, the angleset really changed the handling and the balance point on the bike. Of course, I did it at the same time as the rear travel uprate, so probably some feedback looping in there. Prior to that had lots of miles in the 130mm/100mm with the updated stem/bars and that was really good.
Post angleset, the balance point is more forward (ie not over the rear tire as much), I am having to relearn dynamic positioning.
I'm old and when I last was a regular MTBer bike parks didn't exist, so I'm having to learn all the black diamond stuff. Super fun! I don't think this ride is holding me back yet, based on how I rate myself against random other people on the local trails. I am looking at getting a modern geo hardtail 29er frame to build up and play with in the spring.

I'm a current believer in RAD+reach to set the cockpit. Worked on four bikes for four different people in my family.

1998 Specialized FSR Pro Geo changes:
Stem - 110mm + 15deg -> 60 mm neg 7deg. Stem length entirely dictated by RAD and reach.
Bars - flat 5 deg no upsweep 620mm -> 800mm + 50mm rise +12 deg sweep + 5 deg upsweep.
Fork - 100mm -> 130mm
Rear Squish - 100mm -> 140mm (ish) (via an extended suspension link, this raised BB)
Headset - Ritchey ec34 -> custom ec34 1.5Deg, in the 1.5deg slack mode
HA - 72 deg -> 68 deg
I don't have BB measurements, but it's higher.
Here’s an after and before. I’ve obviously updated the seat angle in the after, I’d just swapped the dropper. The pedal position seat height is bar height.
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I have a 1998 Seven Sola. The fork was stuck to the headset due to galvanic corrosion. I knew if I knocked the fork out, it was likely that I wouldn’t be able to find an equivalent replacement.

It was then that I decided that I should simply get the headtube replaced in order to future proof the frame. A 44mm headtube was installed, along with disc brake mounts. The corroded aluminium rivnuts/nutserts were replaced with stainless.

The frame was a low-slung XC racer with a long top tube, and lent itself well to the mods that I made to it.



I’ve fit a 29er Fox 32SC fork with 27.5 front wheel. Bars are 700mm with a 8 deg sweep. The stem is currently 50mm, but I’ll be swapping to a neg rise 65mm soon.

I’ve been pleasantly surprised at how well it rides, even on chunky descents, despite the limited travel. The BB was tall to begin with, and it’s even taller now. I didn’t find this to be a problem; if anything, it’s great for rocky and rooty jungle singletrack.


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I picked up a 2004 Surly 1x1 earlier this year. I had been thinking about putting a -1 degree angle headset on it, but I ended up just putting a shorter stem than I would have run back in the day, and a Hunter Smooth Move 75mm rise bar on it. I would have thought that the wide bars wouldn't play well with the old geo. The 1x1 has the same 71/73 geo that virtually every MTB used from the early 90s up to 10 years or so ago.





Well, it turns out this absolutely rips! No, it's not going to replace my more modern bikes. And no, I'm not riding double blacks at the local bike park with it, but it sure is a lot of fun on the local XC type trails. And on the newer flow trails as well. I just got a 110mm dropper for it. Can't wait to hit the trails with that.
 

· Dream it, Do it.
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I have a 1995 Kona Explosif. Originally, I was running it with a 100mm stem and a 600mm handlebars. When I did a restoration on it, I went down to a 70mm stem and 740mm handlebars. This combination works surprisingly well. I'm perhaps a bit more upright in position, but getting weight on the front end doesn't seem too difficult.
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This is my '94 model year bike I've fitted with a 60mm stem (from 130mm) and wider higher rise bars (720mm not super wide but up from ~600mm flat bars) to more mimic the seated position of my trail bike. I have zero idea what the geometry is of the bike but it rides just fine like this. Steering obviously felt a lot different at first but I got used to it quickly and it rides just fine this way. I might even say I like the way it rides better since my 45yo back doesn't like being stretched out like I'm in a yoga class for more than 30 minutes. Parts I threw on it were cheap just in case I didn't like the way it rode with the changes. I think the stem was a $9 no brand chinesium cheapie from Amazon and the handlebars were $25 shipped from Ebay. $34 gamble paid off for me.

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· Mantis, Paramount, Campy
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I'd like to know where the myth that "NORBA" geometry bikes of the '90's have short reach came from. Look at the Wheeler posted. I'd bet that frame has a longer reach than anything available today in a comparable frame size.
My 1991 Stumpjumper has ~480mm reach on a 19" frame...M/L by current standards.
 

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Measured the reach at 425mm for my size Medium. Actually longer than I thought it would be. Maybe Wheeler was ahead of their time with Geometry 😄 That's about what a new Specialized XC frame would be, like a Rockhopper or Chisel.
 
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