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drbroccoli

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Discussion starter · #1 ·
I have a 2003/2004 Novara bonanza that I would like to convert to rigid. The fork, an 80mm manitou 6 is dead weight at this point and I'd like to try out the rigid trail riding experience.

My main concern is axle to crown length. My A2C is currently ~450mm. Looking online, I find that "suspension corrected" forks have an a2c of 400-413mm for 80mm equivalents. That seems like a rather significant difference, even taking sag into account. Would switching to a 400mm a2c significantly change the geometry/handling?

Thanks.
 
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#2 ·
Salsa offers their steel fork in two lengths: 425mm (with canti studs) and 445mm (disc only)

That said, with a suspension fork your geometry is constantly changing and depending on your trails you might already be riding with a fork around 413mm a lot of the time. Plus with a rigid fork you will never have it compressing past that point and changing your geometry further like when a susp fork is near the bottom of its travel. 400mm sounds kinda short to me, but 413mm doesn't sounds bad I guess.
 
#3 · (Edited)
Ok perhaps not what you're after as it's a Jump fork but Identiti Rebate XL is 465mm A-C
I personally have a 20mm axle version on the way as I'm converting my STP (came with a 100mm fork) to rigid SS.
10mm axle
http://www.chainreactioncycles.com/Models.aspx?ModelID=35156
20mm axle
http://www.chainreactioncycles.com/Models.aspx?ModelID=35155
other versions
http://www.chainreactioncycles.com/SearchResults.aspx?Search=Identity+Rebate

CRC have a bit of an error in the description of the first one, I'm sure it's 465mm A-C because it's the XL version, the normal Identity Rebate is 425mm A-C (ie the non XL version)

A 20mm difference in A-C would slacken / steepen your head angle by about a degree, slightly lower or raise your bb. Difference in handling would probably be noticeable but I imagine tolerable and not too drastic. If you take into account running say 15mm sag it doesn't leave you too far off the standard Identity Rebate Jump fork which has an A-C of 425.

But this is all just "net knowledge" I'm yet to get my rigid fork to see what difference it makes for me anyway, although I have experimented with various fork travel modes on the bike (80mm - 100mm -130mm and even 150mm!).
 
Discussion starter · #4 ·
It's good to know about those manufacturers. Really I don't want to spend too much and the fork I'm looking at has the 400 mm A2C. I'm curious if that will really mess up the geometry. I'm under the impression that not only will steering be twitchier, my BB will be lower, exposing it to rocks.

Also, my fork is pretty much finished. Even when I stand on the pedals and lean forwards, I don't get more than 20mm of sag.

I'll probably wait until something suitable shows up at a used sporting good store near my place.
 
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#5 ·
Do you know what your BB height is right now? Pedal strikes may or may not be a problem, as bike are generally designed so you won't be in too much trouble at the bottom of your suspension travel, but some bikes are built lower than others.

It will be a bit quicker steering, but rigid forks feel very precise when steering and you will be doing more maneuvering within the trail to get the right line instead of plowing straight over things like with a suspension fork, so quicker steering can compliment a rigid fork well. Always depends on your preferences though

Also, those jump forks tend to be built very solid and heavy, which means they could feel more jarring on the trail than a lighter, mtb-oriented fork
 
#6 ·
drbroccoli said:
I have a 2003/2004 Novara bonanza that I would like to convert to rigid. The fork, an 80mm manitou 6 is dead weight at this point and I'd like to try out the rigid trail riding experience.

My main concern is axle to crown length. My A2C is currently ~450mm. Looking online, I find that "suspension corrected" forks have an a2c of 400-413mm for 80mm equivalents. That seems like a rather significant difference, even taking sag into account. Would switching to a 400mm a2c significantly change the geometry/handling?

Thanks.
Click to expand...
I would get the 400 instead of 425 or 445, it will be better, 425 is good for 100-125 forks.
The longer the fork the more you are missing out on the rigid feel, it flexes. 390 would be optimal if the bikes were designed for it. Don´t even think about going 445.
 
Discussion starter · #7 ·
That's good to hear. It still seems really extreme though, as that would be equivalent to my fork near the bottom of its travel.
 
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#8 ·
Its your choice man, but if you decieded on 445 I would go 425 and so on. Since I have one.
It also depends on where you ride, but with a 80 millimeter fork there was not really any downhill going on in the first place I guess.

Do as you wish but please forget about the 445, it will be very flexible, in a bad way.
 
#9 ·
alivio said:
Its your choice man, but if you decieded on 445 I would go 425 and so on. Since I have one.
It also depends on where you ride, but with a 80 millimeter fork there was not really any downhill going on in the first place I guess.

Do as you wish but please forget about the 445, it will be very flexible, in a bad way.
Click to expand...
I really have to disagree. My 29er rigid fork is 470mm and tracks very well even at speed on very rough trails, and with no discernible bending during hard braking either. Most 29er rigid forks are about this length, are basically identical in construction to their 26" equivalents, and are not known to be flexy. Even longer 490mm forks are somewhat common too, and with no complaints about flex either.
 
#10 ·
I haven't been suggesting any specific length because I'm just not that familiar with 26" fork lengths. But I can say that for 29ers, rigid forks are almost always around 20mm shorter than an unsagged susp fork (470mm rigid for a 490mm 80mm fork, 490mm for a 510mm 100mm fork). Following that rule 425mm sounds like a good length to keep your geometry in a familiar place.
 
Discussion starter · #11 ·
I would imagine it has a lot to do with quality and the overall construction. I will probably be riding fairly roughly, but nothing insane.
 
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#12 ·
I've got my rigid fork now. I brought the XL Rebate which has a 465mm A-C, I thought it was a perfect match to keep the geo of the 100mm fork (I've had a few different forks on my bike but it originally came with a 100mm fork with 491A-C).
Lol after this thread for a minute I thought I made the wrong choice, the bike felt kind of high and slack but that's purely because i"ve been riding a bmx while this one was in bits!

I think you could go either way but I would tend to agree with Boom, the 425mm range would probably be best particularly if you want to keep the same geometry. Otherwise if you went with something at around 465 it would be like upgrading to a 100mm suspsension fork, which would probably be ok for suspension but when it comes to rigids I'm not so sure if it would be as good or not.

I don't know if your fork has a lock out, but if you could lock it out then it might give you a better idea if you should aim to get a rigid that is as close as possible to the current A-C or if you should be allowing for sag etc.
 
#13 ·
so 450mm - 20mm sag = @430mm's give or take, the On One Steel forks are 430mm there only £50 UK, Disk ready, ride well and look good.

Although it's never been a issue, but where the QR normally attaches seems very weak and total lack of any lugs to stop the wheel falling out, this worries me.

Also, you might want longer it'll push your weight back and reduce the weight / pain on your arms. :)
 
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