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What’s the consensus on increasing fork travel? I’m looking at a fairly racy XC bike (Radon Jealous AL - covered in a different thread), which many have commented is too old school with its racy XC geometry, and I’d be better looking at something longer and slacker. Well, I was just thinking, I could maybe increase the fork travel by 10 to 20mm, which I assume would slacken the head angle and lengthen the wheelbase slightly, but also raise the BB and reduce the reach, so would it actually benefit in any way, or would the potential increase in stability be instantly wiped out by other factors?
I’m really just talking hypothetically, out of interest. I’m fairly sure the bike would be adequate for my needs in its standard form.
It will slacken head angle a bit, but also slacken seat angle, raise BB, and reduce reach which are all negatives (arguably). You might like it, though.
Have you considered an angleset?
The rule of thumb always used to be adding about 20mm of travel was ok. But nowadays I’d add 30-30mm with an angle set as well
I used to always stick 120mm forks on a 100mm XC frame eg I had an original 1st gen Blur which was designed for 100mm forks, but I wanted more travel so stuck a 120 fork on it. Done that on a few XC frames over the years.
20mm with -1 angleset usually works well.
@chestercopperpot - so that would slacken the head angle by approx. 2 degrees, is that right?
I have absolutely zero knowledge of anglesets. I can see what they do, but do they not introduce some odd forces on the head tube which could lead to issues? Assume fitting them would void the warranty on a new bike too?
There and there abouts.
I doubt you will rip the headtube off any recently manufactured bike from a reputable MTB brand and I doubt you are doing Josh Bender style hucks. Just look how big the weld area is on virtually all modern alu frames (oversized/flared top and down tubes sandwiched together) with tapered headtubes.
Nowadays you can do anything... following on From Brendog on the Scott Spark look what Wiggle are selling as an XC Fork.
their 'HD' models of the jealous are exactly that - but only 10mm added on.
I don't think you can get slacksets to fit is41 headsets, I'd look for a different bike. its worth noting that, due to being a hardtail, as you go through fork travel the head angle steepens (probably when you need it most), so at full travel that thing will have a ~74 head angle - this obviously also happens on all hardtails, but useful when comparing it to full sus bikes
I have a 2008 Giant Anthem which was designed for 80 mm forks. I run 130 mm Revelations on it, it's a big improvement as a trailbike.
The "ripping the headtube off" thing is mostly nonsense. The axle-crown length of forks is in the ballpark of 500 mm, plus you have another 300 mm or so of wheel beneath that. A 50 mm increase in fork length is less than 10% increase in leverage, so the bike isn't going to explode in flames just from that. A 20 mm increase is inconsequential.
Where you might run into trouble is if you take a lightweight XC frame, put longer forks on it, and then thrash it down rough descents and over big drops. That will stress the frame much more than just the longer forks, so you need to ride it sensibly.
due to being a hardtail, as you go through fork travel the head angle steepens (probably when you need it most)
It steepens when you need it least - braking on steep descents. Suspension bikes do this, but it's even worse. On climbs, they squat so the HA slackens, on descents, the rear suspension extends so the HA steepens.
Going back to that other thread you had 2 bikes that were a little more trail than the Radon - that you wouldn’t need to put a longer fork on to try and make it a little less xc.
I’d just buy something more trail orientated (but still pretty light) if you think you might want that. The Orbea looked decent to me.
Why don’t you try and test ride a few different types of hardtail and see which you like the feel of? Radon might be difficult as might Canyon but I’d expect you’d be able to find something with similar geometry to try. The Orbea might be test rideable.
My last hardtail was a Vitus Sentier running a 140mm Pike, reasonably heavy wheels (Dt e1900’s), hefty brakes and a mid range 11 speed drivetrain. Weighed about 28lbs and it was good at virtually everything I tried. Long ish road / bridleway rides during lockdown were decent, but at the other end I’ve also done a little bit of uplift at Flyup 417 on it. Think it was a 432mm reach (I’m 5’9), 66 degree headangle, 73 degree seat angle, 425mm chainstay / relatively low bottom bracket.
It was a perfect middle of the road hardtail that you could pretty much anything on. With the dropper post down it was even really fun on a pump track. An XC hardtail will be lighter (although if I’d had decent wheels and less heavy tyres / brakes I could easily have taken a chunk more weight off the Sentier) and possibly have a longer stretch from the saddle to the bars but it will be a bit twitchier at speed.
@joebristol - without wishing to go too far off topic, I agree, the Sentier looks good, but the Rapide looks closer to my perfect bike. The only issue is the top-end alu is relatively weak spec, and the bottom-end carbon in too expensive! If they did a higher spec alu which sat in the middle on price point, I think I'd have exactly what I'm looking for. Also, I prefer the 32-10/52 12-speed drivetrain on the Radon.
I guess my point wasn’t to look at Vitus, more to highlight that trail hardtails are pretty good do it all machines, and very focused XC hardtails are less good all rounders but very good at what they do. A test ride of a trail one vs a focused XC one might just show you the difference and tip you one way or the other.
On the Vitus owners Facebook page there was a guy there who bought a really nicely specced carbon rapide and it lasted a month before he swapped for something more trail. He was also thinking g about joining road sections up with gravel tracks and some trail centre stuff thrown in. I can’t remember what he went for in the end - it might have been the 29er Sentier or it might have been the full suss Mythique.
@joebristol - yep, I get you. Man, this decision is driving ferking crazy. 😩
Heart says Radon. Head says something else.
Joe says test ride both types of ht over as varied a terrain you can and see which feels best 🤷♂️