REVIEWS DEALS BIKESHOPS TRAILS

140mm fork on 120mm frame, what to look for?

7357 Views 6 Replies 5 Participants Last post by BaeckerX1, Jul 27, 2010

BaeckerX1

Discussion Starter · Jul 26, 2010 (Edited)

I recently purchased a new frame with 120mm rear travel. I had a 140mm Rockshox Revelation Dual Air with the 20mm Maxle Lite, so that's what was put on there. I really like the stiffness of the thru-axle and the fork performance. I'm not looking to buy another fork. I'm wondering if I should use the spacers to reduce my fork to 120mm. The fork has no travel adjust.

So far I've only ridden this bike on the trails once. I'm too out of shape to really notice if the geometry is affecting the climbing ability or not. It does rail on the downhill though. It seems to feel really good bombing down some singletrack, and much more confidence inspiring than my last bike. I think the slack head angle helps here. The default HA on the bike is 69.5 with a 120mm Fox Float, which would make the bike somewhere around 68.5 with the 140mm Revelation? Just guessing there.

If I'm trying to evaluate the characteristics and determine if I should reduce it to 120, what kind of things should I be looking for? I just purchased this frame and haven't ever run it with a 120mm fork, so I have no idea what the bike would feel like normally. Do you think the 140 fork on it will adversely affect the handling characteristics or overall performance? Will it be negligible or significant? I realize without actually riding it that it's all armchair engineering over the internet, but hopefully with some help I can get ideas of things to look for on my next ride.

(The LBS where I purchased my frame said that the frame would take it and that it wouldn't void my warranty.)

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the sloth

· #2 · Jul 26, 2010

The front end will tend to wander a bit more at 140 on steep climbs. You'll have to combat this by leaning forward and applying more weight to the bars. Whether or not this is a problem is up to you.

I really like the descending and all around riding at 140 compared to 120, so I usually leave my Talas out at 140. Long steep climbs I'll dial it down to 120.

Try riding at 140 for several rides, then give it a go at 120 to see which you prefer.

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BaeckerX1

Discussion Starter · #3 · Jul 26, 2010 (Edited)

the sloth said:
The front end will tend to wander a bit more at 140 on steep climbs. You'll have to combat this by leaning forward and applying more weight to the bars. Whether or not this is a problem is up to you.

I really like the descending and all around riding at 140 compared to 120, so I usually leave my Talas out at 140. Long steep climbs I'll dial it down to 120.

Try riding at 140 for several rides, then give it a go at 120 to see which you prefer.

Yeah, I'm definitely going to be riding it at 140 for awhile. I'm willing to sacrifice a little on the climb for more speed, stability, and fun going downhill. Getting in shape is the most important thing.

How difficult is it to add and remove spacers in a fork? The main reason I'm asking this question is because I'm not really familiar with taking apart forks and not sure if I'll have to take it somewhere to have this done. I just want to be sure before changing things, if at all.

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derby

· #4 · Jul 26, 2010

Try it lowered to 120mm travel. You can always put it back to 140mm. It will probably climb easier for you immediately, but downhill may feel too "over the bars" and scary braking hard, locking up the rear out of control easily if you were used to the taller front end and slacker geometry.

Your fit and weight center over the cranks matters more than anything for climbing ease. You could try moving the seat forward about 1/2 inch with the taller fork setting to have about the same climbing ease as lowering the fork but keep the taller fork and slacker handling.

Slacker forks are easier and smoother over very rough and loose terrain and downhill - and easier to ride in general if you haven't ridden much off road before.

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Gman086

· #5 · Jul 26, 2010

I leave mine at 140 on my trail bike BUT I went with lower rise bars and all spacers over the stem instead of under to lower the bar height as much as possible. That's the best of both worlds if you ask me. Plus having slacker geometry teaches you to be a faster rider since you have to lean your bike more thru the turns instead of steering thru them.

Have FUN!

G MAN

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mountainbiker24

· #6 · Jul 27, 2010

You could also bump up the negative air pressure another 10 psi in relation to the positive chamber. That will increase small bump sensitivity a bit while reducing the travel a few mm. My dual-air Pike shows 135mm of stanction when set up with a bit more neg pressure than positive.

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BaeckerX1

Discussion Starter · #7 · Jul 27, 2010

mountainbiker24 said:
You could also bump up the negative air pressure another 10 psi in relation to the positive chamber. That will increase small bump sensitivity a bit while reducing the travel a few mm. My dual-air Pike shows 135mm of stanction when set up with a bit more neg pressure than positive.

Good idea, thanks for the tip! I'll test this out. The manufacturer said the bike was designed for use with 120mm or 130mm forks, so even getting a tad closer to 130 would be nice to try.

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