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Raising the front end of a classic XC rig...

2K views 12 replies 9 participants last post by  scottzg 
#1 ·
I'm considering raising the front end of my classic FS XC rig by one or more of the following means. I'm interested in knowing the merits of the various schemes.

1. Install a fork with more travel. The current travel is 80mm or so and I believe the front of the bike will come up quite a bit by moving to something like a 120mm fork.

2. Installing a stem with some rise to it. Currently the stem is a 140 zero rise.

3. Installing riser bars. Currently the bars are flat Syncros Ti bars.

What I'd like to know is something about how the handling will vary based on the three options above.

Thanks in advance!
 
#7 · (Edited)
You're gonna mess something up no matter what. You can really only benefit here because old-school XC geo is awful.

Fork- slacks both head and seat angle. Raises the bottom bracket. Raises the bars. This will all add up to moving your weight quite a bit rearward, making it more stable descending, apt to wander climbing, and more sensitive to weight shifts.. You can compensate by moving the saddle forward and/or lowering the bars, which will shorten the cockpit and can do a variety of things to how the bike descends depending on how you locate yourself on the bike. Modern forks tend to track significantly better than 'classic' ones, and can make a big difference even at low speeds like you describe, especially for heavier riders.

Stem- God that is a stupid stem, a bike designed around a stem like that put me off MTB for 10 years. Moving the bars up/inward will make it easier to loft the front end, and make the bike less OTB friendly, but encourage understeer, shorten the cockpit, and make the bike wander on steep climbs. With a 140 stem on there from Ells, it's unlikely you can put something on there short enough to make the bike feel 'OK' by modern standards.

Bars- riser bars accomplish what a riser stem does- move your hand position. A wider bar will slow down the steering a bit, which will most likely improve the experience.

In general, late 90s- early 2000s XC bikes were just designed with a different set of design parameters- short wheelbase, fast handling bikes were preferred, and you rode them by being super careful about where the front wheel went, most likely on smoother trails. The Truth is a more forgiving design overall, from a time period when design was sensibly moving away from XC race niche design.

(there's a ton of bias in this post, obviously, but that's for entertainment value)
 
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#8 ·
Really good info here. Thanks. I should say that my stem wasn't from Ellsworth. I bought the frame and built it up myself. I'm nicely stretched out on it and frankly, it feels very good. The trail I ride rocky and with lots of roots and short but very steep and tricky climbs. There are some drops coming down that will put you over the bars if you hit them straight on. So, descending requires care, and this 55 year old body prefers to stay in one piece. I love to climb most of all so I'd not want my front to begin wandering very much, yet a little more safety (ease--control--secure feeling) coming down would be a nice benefit.

The easiest thing is to pick up a shorter stem with some rise to it. I think I'll start with that. A side benefit to going to a newer fork would be the ability to use a front disk brake, which everyone tells me is worth the price of admission...
 
#2 ·
Go with the stem or the riser bars. In my opinion, try and keep the original geometry intact, i.e. the head tube angle and the bb height. Putting a steeper fork on it will upset the original design.

But the real question is, "Why do you wan to to do this?"
 
#3 ·
I would not go past 100mm travel and I'd go with riser bars and a slightly shorter stem (~100mm).

Bars that are too high just feel wrong. IDK what it is. It's like you're rowing a boat instead of riding a bike. I think you lose leverage.
A longer fork might start giving you that flip-floppy steering. Also bad (for me, anyway).
Your bottom bracket will be slightly higher, meaning your center of gravity will be higher, which can reduce your cornering ability.
No change is really "bad" until you change it too far. I do wonder what you're getting after, though.

-F
 
#4 ·
What I'm getting after--why my questions--is this. I recently purchased a newer version of my bike for my fiance. It has a 100 fork that raises the front end of her bike a full two inches higher than my front end. My fork from hub to the bottom of the headset is 17". Hers is 19". Add to that--she has a short riser stem plus riser bars--so her hand position is 3.75" higher than mine. Interestingly, she is on a small sized frame, mine is medium. My bike is an Ellsworth FS/2xc from 1997 and hers is a Truth from 2003.

I'm positioned like we used to do... Like my road bike. She has a more "modern" upright position.

What I noticed, when I adjusted her saddle for my height and pedaled around a bit, is that I could turn tighter circles on her bike. I don't know how well I'd climb with so much of my weight so far back--and presumably I'd descend better--so it has me thinking what it would be like to adjust my positioning a bit. I've thought of three ways to do it. Fork, stem, bars. An added benefit: if I do the fork, it gives me the option of going to disk brake in front (My rear triangle does not have tabs for disk brakes).

What I'd like to know is what you guys have begun to discuss. The design of the bike is the way I have it set up. So I'm messing with that... And the question is which way to mess with it will create the fewest oddities in handling while giving me... What? Any improvements at all?
 
#6 ·
140 zero rise stem is pretty long, XXL by today's standard. I actually consider my 100 stem a long stem:)

You can comfortably raise your travel to 100-110 max and not feeling too slack, 120mm may be a bit much. I swapped out 80mm fork on my hardtail to 100s and they handles much better. Also swapped 120 stem to a 90 mm stem, as well as narrow flat bar to wider riser bar and it feels much better.
 
#9 ·
I consistently put longer travel forks, shorter stems and wider/higher bars on my bikes than what they came with stock back in those days. Though some people have a habit of saying any change to geometry 'screws things up', that's only the case if the bike company dialed in the geometry and part spec 100% perfectly for every person that ever bought that particular model of bike, which is of course a silly presumption. I like my bikes a bit slack, and always have, so changing the fork isn't 'screwing up' anything, it's making the bike better match my preferences, and since it's MY bike, I figure, I'll make it handle any damn way I please.

:thumbsup:
 
#10 ·
I consistently put longer travel forks, shorter stems and wider/higher bars on my bikes than what they came with stock back in those days. Though some people have a habit of saying any change to geometry 'screws things up', that's only the case if the bike company dialed in the geometry and part spec 100% perfectly for every person that ever bought that particular model of bike, which is of course a silly presumption. I like my bikes a bit slack, and always have, so changing the fork isn't 'screwing up' anything, it's making the bike better match my preferences, and since it's MY bike, I figure, I'll make it handle any damn way I please.

:thumbsup:
Now THAT makes sense! Great thinking... Thanks!
 
#11 ·
Just remember , even small changes feel pronounced on a mtnbike.

I will say though.....140mm stem is looooong even for XC. lol
I'm in the XC camp myself and love to climb. I also much prefer steep head angle, low BB for slow climbs.

If it were my bike, I'd simply go with a 110mm stem with 6deg rise and be done assuming the fork is in good condition.

You could possibly get by with a 100mm fork but I'd avoid a 120, could stress the head tube.
 
#12 ·
Okay, I have old mtb bikes and I have forks that are about 20mm more travel than designed and I see no problem, so a 100mm would work... now trying to find that 100mm fork (v-brakes???) is another issue and that would be my last resort.

But you can make changes with the stem and bars. Going from a 140mm to a 100mm may be a bit too much of a drastic change, but I have gone from a 135mm (<10 degree???) to a 120mm with a 20 degree rise and it made a big handling improvement on an old GT. The front wheel was way too loaded before I made the change. Keep in mind that stem angle impacts handlebar reach.

If you get riser bars, that will raise them more, but unless you shorten the stem you will still be reaching, albeit not as low.

John
 
#13 ·
If it takes a 140mm stem to make it fit, you're on too small of a frame. One frame size is usually about 15-20mm in reach, and you expect to run about 100mm of stem on a racy xc bike. I assumed ells put that stem on and designed the frame around a suuuuuper short top tube.

It's worth demoing a newer xc bike and see how you gel with it before going too far tweaking what might never work great.
 
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