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So I've just made the jump from an older, heavier 26er (2008 Heckler with Lyriks & 28mm rims) to a modern trail 29er (2014 Stumpjumper with Revs & 24mm rims). Its a great improvement in every area, apart from dealing with rock gardens and rough ground, where I'm finding it harder to keep on line and plough through it in the same way. Certainly not as confident to just let go and hang on.
So is it the lighter fork, narrower rims, larger wheel-size or just a combination of all 3? Any opinions on what upgrades have the biggest effect on confident steering - new fork vs new rims?
FWIW, I swapped the stem & bar from my old bike so no difference there.
Ditch the Rev. Then get a proper carbon rim. I did both, steering now sorted.
Rims and Fork.
Wheels probably. It's the weight not the width that counts.
You could swap the rev for a pike but if you still have flexy wheels the bike won't feel any better.
Wheels with wide rims are needed for 29er's using ryde trace trail on one of mine now and give very precise steering and allow me to climb quicker than before. Carbon rims do the same job but cost more.
I went from revs to a pike, made a massive difference. I have just got carbon rims and am still getting use to them. Very stiff and in the dry this is quite unnerving. I probably need how to learn how to ride properly now.
Why do you think wide rims are necessary?
If anything 29ers need narrower tyres due to the longer contact patch.
That's my experience anyway.
Because when i try wider rims with the same 2.2" tyre the bike just feels quicker as quick as with my carbon tubular wheel with dugast tyres. Also i have been able to drop the pressure a bit without getting that squrimy feeling in the bends.
...Why do you think wide rims are necessary?
If anything 29ers need narrower tyres due to the longer contact patch.
That's my experience anyway...
What? Why so you think this?
Also, you don't need carbon rims for stiffness. Hope Enduros are plenty stiff enough and that bit more weight helps stability too.
I gradually upgraded my steering parts when I went from a MK1 26er Nukeproof Mega with Lyriks to an SB95. I went for a Manitou Tower 140 at first on the SB95. A Pike was the first upgrade and it was noticeably better at tracking over rough stuff (Instant Strava results. PRs on first ride!). Next was a Renthal bar (740mm) and stem combo. Again, a further speed increase. The final component was a Maxxis Minion DHF 2.5.
...Why do you think wide rims are necessary?
If anything 29ers need narrower tyres due to the longer contact patch.
That's my experience anyway...What? Why so you think this?
29er tyres have more rubber touching the ground for a given width = more drag/grip.
I'm using 2.3in tyres, vs 2.4 or 2.5 on my 26in bike to get a similar balance of grip/rolling speed.
Ok. And what does that have to do with steering stiffness?
For any given tyre pressure, a wider tyre will have a more circular contact patch than a narrower tyre. The area of the contact patch will be the same.
Ok. And what does that have to do with steering stiffness?
Nothing.
Did you read the comment I was replying to?
About wide rims being necessary for 29ers?
Sheesh.
My experience is that when I'm pinging though rocky trails on a 26er, it's easy to make lots of small adjustments, whereas on a 29er, it's more difficult to make those small adjustments, the bike holds a line better, so you need to be smoother with steering and pick your lines further in advance.
No clue whether this is anything to do with what you're experiencing!
My experience is that when I'm pinging though rocky trails on a 26er, it's easy to make lots of small adjustments, whereas on a 29er, it's more difficult to make those small adjustments, the bike holds a line better, so you need to be smoother with steering and pick your lines further in advance.
Agree with above. Probably just a case of getting used to the 29er. Also nothing wrong with Rev fork when set up properly. Transformed my Rumblefish by replacing the twangy Fox with a Revelation dual air.
I am alot faster on all terrain on my 29er compared to my 26ers past and present.
As for wide rims being necessary they are not but seem helpful. I prefer the feel of a stiff rim and wider rims are stiffer. I have a wheelset with velocity Blunt SL rims 20mm internal width and now one with Ryde Trace trail rims. The tyres are the same the profile though is not. On the wider rims I have feel the bike is more stable over the lumpy stuff and fast bends. I can also run the pressure a few psi lower. to me the difference is real and I might be selling those narrower wheels to some of you who love narrower XC rims. I simply won't be using them much again.
If 29er have more drag as posted above please explain why then I can ride so much quicker on a 29er on any terrain I have tried. 29er's have lower rolling resistance because rolling resistance is inverseley proportional to the wheel diameter but that not the only advantage 29er's have. The contact patch of a 29er compared to a 26er cannot be different in area for a given load but it is different in shape and thats the difference.
I am a wider rim convert. Yet to try wider than 24.8mm internal width. I suspect the will be a point at which the extra width starts to have a down side not sure where that is yet though.
If 29er have more drag as posted above please explain why then I can ride so much quicker on a 29er on any terrain I have tried.
I'm faster on my 29ers almost everywhere too. It's the momentum and roll-over-ability mainly I think. More drag doesn't mean slower than a 26er. Just slower than other less draggy 29er tyres.
I've got no problem with wider rims, my FSer is on 25mm internal width rims. They're great. But my HT is on 19mm internal width rims - and they're great too.
And I've found 2.3in tyres fine for everything from racing XC to epic Lakes hike-a-bike rock-fests (done both this week!).
I wouldn't normally get involved in these pseudo-sciencey STW debates, but I felt I've got some useful knowledge on 29er wheels and tyres that I've learned by trial and error - and that sharing might help the OP and others.
Wider/stiffer rims and wider-spaced hubs are useful. If I was changing forks for stiffness I'd be looking for the cost pros and cons of going for a Boost-width fork + hub at the same time.
I swapped the stem & bar from my old bike so no difference there
Recently built my first 29er and it needed much wider bars than a 26er to feel the same. You're probably not feeling flex, it's probably the extra leverage exerted by the wheel on the bars. What width do you have on there?
Good points from Jameso and Molgrips there.
Bar width is personal, but I've settled on 785mm.