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Discussion Starter · #1 ·
Hello all. This is a great forum you have! I have an old Trek 920 single track that I'm wanting to do some upgrades to this winter. My goal is to get a suspension fork that will allow me to upgrade to front disc brakes. I also want to install higher rise handlebars (it's really a commuter bike). I know that I will need to change my headset from threaded to threadless, and choose the proper forks to accept disc brakes, and also be aware of choosing forks without too much suspension to throw off the steering geometry. I believe I will have to get a new front hub to accept the disc brake rotor as well, which of course involves re-lacing the wheel.

So far it sounds like I know what I need, right? Yeah...on paper I think I do. What I need help with is choosing the correct components and suggestion on what to look out for. This is strictly a commuter bike that will likely only ever see crushed gravel at most (no real off road riding). For the disc brakes, the value for the money seems to be the Avid BB7 mechanical disc setup. I have NO idea what forks, headset, stem, or bars to buy. I'm looking for the best bang for the buck, and (besided the brakes), I'm not against buying something used.

Could you experts offer me any suggestions? I know I've asked a lot of questions in my first post....but I wanted to get all the details listed to help those who may reply.


Thanks in advance,

Warner
 

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Discussion Starter · #2 ·
Shopping list

Okay...while I was waiting for a reply, I put together what I think will be a viable shopping list of parts for my planned upgrades. In addition to these parts, I know I need a new front hub to hold the rotor for the disc brakes. I'm thinking the Shimano XT would be a decent hub for a reasonable price. Any feedback is welcome.

Thanks,

Warner

This is all the "stuff" I think I'll need to convert my old Trek 920 to front suspension, front disc brake, and higher rise handlebars. I also need to order the correct front hub for the disc brakes and have my wheel re-laced (the hub I want is around $50). Total cost for all of this is going to be in the $300 range. I think the bike will be safer and more comfortable, though.

Warner

All of these parts are from pricepoint.com

34191
2009 Rockshox Dart 2 Post Black 80mm $89.98

30137
Avid BB7 Mech Disc Brake Grey Fnt/Rer 2009 160mm $44.98

43033
FSA Pig Headset $19.98

40100
Sette Duo O/S 31.8mm Riser Handlebar - 2014 2.5" Rise $21.98

18005
Avid Speed Dial 7 Brake Levers 2009 $17.98

21039
Sram Pit-Stop Full Metal Jacket Disc Brake Cable Set 2009 $19.98

69136
Truvativ AKA All-Mountain Stem 2010 Black 110mm $34.98

Subtotal : $249.86
 

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What year is your 920? First n foremost, make sure that you have a 1 1/8" fork/headset.
If it's a 1", suspension fork options are extremely limited.
Looking at vintage-trek.com, looks like the 920 was made in '94 & '98. The '94 is probably not suspension corrected (the shx models were). It will change the handling considerably.

The dart isn't much of a suspension fork & it's heavy! Otherwise, list looks fine. I'd go for a new front wheel, rather than rebuild old rim w/ new hub/spokes. Deore & LX are fine hubs too.

For a commuter, I'd honestly skip the dart (or any other low end suspension fork) & just go for a nice fat front tire (ie schwalbe big apple/super moto 2.35 x 26) for some passive suspension & a rigid fork (lots of options in the $50-100 range). It'll be a few pounds lighter.
 

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All that^^^^ There can be some definate compatibility issues when you go back to older bikes or any time a 'standard' was in the midst of changing (threaded to threadless...1", 1 1/8", and 1 1/4" steer tubes...)


My only addition would be...do you really want a 110mm stem. Generally a taller bar would go along with/suggest that you would want a more upright shorter reach set-up.


Might be worth a call to trek so see if you can get some solid info about the frame. Epecially the head tube/steer tube configuration....AND the original axle to crown (fork length measurement) measurement that the frame was designed around.
 

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davep said:
My only addition would be...do you really want a 110mm stem. Generally a taller bar would go along with/suggest that you would want a more upright shorter reach set-up.
Here's an excel spreadsheet that'll help with stem length/rise/reach. There's also some charts on the internet (ie habanero cycles).
stem angle info at this thread http://forums.mtbr.com/showpost.php?p=4293182 (post #7)
 

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Discussion Starter · #6 ·
logbiter said:
What year is your 920? First n foremost, make sure that you have a 1 1/8" fork/headset.
If it's a 1", suspension fork options are extremely limited.
Looking at vintage-trek.com, looks like the 920 was made in '94 & '98. The '94 is probably not suspension corrected (the shx models were). It will change the handling considerably.

The dart isn't much of a suspension fork & it's heavy! Otherwise, list looks fine. I'd go for a new front wheel, rather than rebuild old rim w/ new hub/spokes. Deore & LX are fine hubs too.

For a commuter, I'd honestly skip the dart (or any other low end suspension fork) & just go for a nice fat front tire (ie schwalbe big apple/super moto 2.35 x 26) for some passive suspension & a rigid fork (lots of options in the $50-100 range). It'll be a few pounds lighter.
I am pretty sure it is a 1 1/8" fork/headset. I am also pretty sure mine is a '94 model. How can I tell for sure if it IS 1 1/8"? I know the Dart is nothing special, and if I were ever going to go off road, I wouldn't pick that fork. I am just looking for a little bit of cushion for my commute to work and back. Weight is really not an issue....and here's why...this is actually a motorized bike...capable of around 40 mph and gets well over 100 mpg. My commute to work is about 20 miles each way and I can make it in 45 minutes, regardless of traffic (since I'm riding on the shoulder of the road). Pedaling that far and arriving in any shape to work before taking a shower just isn't feasible. I'm not lazy...it's just not feasible for me (and I can't pedal at 30mph either!).

Your suggestion about the whole new wheel was probably a good one....but one that came too late as I have already ordered the hub. :madman:

Thanks for the response,

Warner
 

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Discussion Starter · #7 ·
davep said:
All that^^^^ There can be some definate compatibility issues when you go back to older bikes or any time a 'standard' was in the midst of changing (threaded to threadless...1", 1 1/8", and 1 1/4" steer tubes...)

My only addition would be...do you really want a 110mm stem. Generally a taller bar would go along with/suggest that you would want a more upright shorter reach set-up.

Might be worth a call to trek so see if you can get some solid info about the frame. Epecially the head tube/steer tube configuration....AND the original axle to crown (fork length measurement) measurement that the frame was designed around.
Thanks for the response. I did end up ordering a 90mm stem, so I didn't go with the 110. Hopefully the darn thing DOES have a 1 1/8" fork. If not, I may end up using the new parts on a Giant mountain bike that I got for free from a co-worker....we'll see!

Thanks again,

Warner
 

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Discussion Starter · #8 ·
logbiter said:
Here's an excel spreadsheet that'll help with stem length/rise/reach. There's also some charts on the internet (ie habanero cycles).
stem angle info at this thread http://forums.mtbr.com/showpost.php?p=4293182 (post #7)
Thanks for the response. I did check out the spreadsheet, but don't have all the variables to make good use of it....plus I ordered the riser bars (2.5") which would throw the whole thing off, right?

Warner
 

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Discussion Starter · #10 ·
davep said:
^^^^ Very cool! sounds like a great deal if you have a different climate where you live (I am in seattle)...
I'm in the Chicago area...so we get every type of weather that there is. Right now it's too cold and icy to ride (for me, anyway), which is why I'm in "project mode" with the bike.

Warner
 

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Discussion Starter · #11 ·
logbiter said:
What year is your 920? First n foremost, make sure that you have a 1 1/8" fork/headset.
If it's a 1", suspension fork options are extremely limited.
Looking at vintage-trek.com, looks like the 920 was made in '94 & '98. The '94 is probably not suspension corrected (the shx models were). It will change the handling considerably.

The dart isn't much of a suspension fork & it's heavy! Otherwise, list looks fine. I'd go for a new front wheel, rather than rebuild old rim w/ new hub/spokes. Deore & LX are fine hubs too.

For a commuter, I'd honestly skip the dart (or any other low end suspension fork) & just go for a nice fat front tire (ie schwalbe big apple/super moto 2.35 x 26) for some passive suspension & a rigid fork (lots of options in the $50-100 range). It'll be a few pounds lighter.
Logbiter, I went back and checked the frame geometry on the '94 Trek 920 and it is identical to the geometry on the bikes they sold that same year that WERE suspension bikes, so I should be okay on that.

I ended up getting lucky with the hub - it was on backorder so I cancelled my order and checked on Performance's web site and found an entire wheel, already laced and ready to go - marked down from $110 to $60, so I went with that. The local Performance shop had it in stock so I was able to save on shipping (and waiting) charges by picking it up there locally. When they rang it up, they told me "That will be $115 something"...I told them it should be $59.99 plus tax as it was online. The girl checked online and matched the price. In the end it cost me $13 more for the entire wheel (already laced up!) than the hub alone would have cost. It's probably not as nice a hub as the one I ordered, but it'll be fine for my use. Here's a link to the one I bought (Forte' Terramax):

http://www.performancebike.com/weba...oreId=10052&catalogId=10551&productId=1034199

Tonight I'll start tearing the old stuff off the bike, and make sure that it IS in fact 1 1/8" - all of the Trek documentation I can find suggests that it is....so I'm cautiously optimistic. I also have a mid-90's Giant mountain bike hanging in the garage (got for free from a co-worker) that I will use if the Trek isn't the right size. ONE of them should be 1 1/8" and I suspect that they BOTH are.

Thanks again,

Warner
 

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Discussion Starter · #13 ·
nitropowered said:
Why suspension fork if you are just commuting on it?

I would just get a ridged fork with disc tabs. Save money, save some weight, save maintenance.
Just wanted a little more plush ride. My 20 mile (each way) commute takes me down a very busy highway (with a decent shoulder) that gets a fair amount of debirs on it. I am using the Specialized Armadillo nimbus tires on it with spinskins inside for that reason. Having a blowout on the front tire at 35 mph wouldn't be too much fun, and a rear flat (which I've had) is a pain to change due to the engine on the rack. Since changing over, I haven't had a single flat. Sometimes the debris can't be avoided and I run over it and the suspension forks will make the ride a little smoother. Weight really isn't much of an issue on this ride - it's got loaded panniers, a fairly large SLA battery (for the 55 watt headlight and horn)...so a pound or two here or there doesn't make any difference, really.

Warner
 

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Discussion Starter · #14 ·
Photos

Here are a couple of photos so you can see what it looks like. One is with all the garb on it...and the other shows the intitial build up. I can post new photos after I'm done with the current upgrades if anyone is interested.

Warner



 

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cool! that looks like 1 1/8".
Is that a fire extinguisher you got mounted there? :smilewinkgrin::ciappa:

Sorry, I meant to post how to check headset/steerer diameter earlier. Easiest way to tell is by the diameter of your current stem quill (part that inserts into the steerer tube). If it's 25.4mm/1", you're headset is 1 1/8". If it's 22.2mm/7/8", it's a 1". The diameter will be stamped on your stem, if you pull it up/out. Nice explanation & chart ala Sheldon Brown.
 

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Discussion Starter · #16 ·
logbiter said:
cool! that looks like 1 1/8".
Is that a fire extinguisher you got mounted there? :smilewinkgrin::ciappa:

Sorry, I meant to post how to check headset/steerer diameter earlier. Easiest way to tell is by the diameter of your current stem quill (part that inserts into the steerer tube). If it's 25.4mm/1", you're headset is 1 1/8". If it's 22.2mm/7/8", it's a 1". The diameter will be stamped on your stem, if you pull it up/out. Nice explanation & chart ala Sheldon Brown.
Hahaha....no, but that's a common question! It's a fuel bottle....the approved type. Since it's a 2 stroke I put the pre-mixed gas in those bottles. I carry two of them. Two bottles plus what the little gas tank holds is enough to go more than 60 miles. Thanks for all the info!

Warner
 

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Discussion Starter · #17 · (Edited)
Well, it's DEFINITELY 1 1/8", because I have the threadless headset installed (the cups at least). Now I just have to get the race installed properly on the fork, buy some spacers, and get the star nut installed into the fork. To get the headset cups seated into the frame's head tube, I made my own press using a 1/2" piece of threaded rod and some large, thick washers to push evenly on the cups as I tightened the nuts on the threaded rod. Worked like a champ! I could likely find a way to safely seat the race on the fork, but the star nut seems like it really wants a specialized tool to install it to the proper depth and squarely in the fork tube. I may actually break down and see if the local bike shop charges much to do this. It'll take them all of 5 minutes with the right tools.


Warner
 
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