I am in the process of upgrading my 29er and as I am changing from QR to 15mm forks I need to change my wheels too and am going to build the wheels myself.
Now given I currently use my 29er for both XC riding and bikepacking I am rather confused regarding the correct rim width, spoke count and benefits of carbon fibre vs aluminium on MTB wheels.
I am running 2.2 Maxxis IKON tyres and am contemplating going to 2.4s for bikepacking.
So do I go for a 35mm wide enduro carbon rear rim with 32H spoke count so that I have a really strong wheel for bikepacking OR does the wider rim mean that I can cut the number of spokes down to 24 and still have a really bomb proof wheel that is laterally stiff?
In terms of the front wheel I have to go for a 32H rim as the SP dynamo hub comes only in 32H, but would a narrower rim be a better option on the front.
One final question. Benefits of Carbon Vs Aluminium for MTB wheels?
Thanks
32 is probably more than you need, depending on how big you are, and how lightweight or not your gear is and where you ride.
I've got a set of Stans alpha 340 on my monstercross, I've smashed them around the trails pretty hard, bottomed out the rims on rocks on fast descents, smacked into a tree stump at 15mph that stopped me dead. They're still true, I haven't been near them with a spoke key and they're 24 front, 28 rear on rims that some complain are too noodly for cx.
If you're on 35mm rims, you should definitely be able to get away with less than 32.
But. Given that you're forced into 32H at the front, I'd go 32 at the back as well, because.
Further reading: http://www.slowtwitch.com/Tech/Debunking_Wheel_Stiffness_3449.html
Jolly interesting that, actually
Carbon - expensive and light and stiff
aluminium - much cheaper and not much heavier, and probably plenty stiff enough.
Thanks for the link and your insite. It does not, however, answer the question of how noticeable it is to run a 2.4 wide tyre on a 35mm wide rim over a 23mm wide rim. I suspect the wider rim will give the feel of a laterally stiffer wheel just because the tyre on the wider rim is not bulging as much as it does on a narrower rim?
I'd stick with 32 spokes regardless of rim with the SP dyno hub. It's got quite narrow flanges and doesn't build into a stiff wheel.
That might explain the reason why I felt the wheel rather noodly when I was out of the saddle and climbing? Is there any way you can build up a laterally stiffer wheel with a SP dynamo hub?I'd stick with 32 spokes regardless of rim with the SP dyno hub. It's got quite narrow flanges and doesn't build into a stiff wheel.
Would a carbon rim make any difference or is it down to the hub as to how laterally stiff the wheel is?
So do I go for a 35mm wide enduro carbon rear rim with 32H spoke count so that I have a really strong wheel for bikepacking OR does the wider rim mean that I can cut the number of spokes down to 24 and still have a really bomb proof wheel that is laterally stiff?
35mm on a 2.2" tyre? Is that internal or external? Sounds very wide for that sort of tyre.
Mate has these https://www.notubes.com/flow-mk3-wheelset with 2.5" maxxis, I'm running the same on the 25mm version and it would make the anything smaller far too wide IMHO.
Just really, how much weight is there to be saved by reducing the number of spokes from 32 to 28 or even 24?
32 holes should be easier to get for hub/rim spares and will be that bit more tolerant when you break a spoke half way round the HT550 🙂
35 mm wide rims are gnarly trail and nearly + size territory.
35mm is the external width. I was looking at these rims.35mm on a 2.2" tyre? Is that internal or external?
[url= https://www.lightbicycle.com/EN928-asymmetric-rim-profile-carbon-29-inch-mountain-rims.html ]LB Carbon Rims[/url]
I take the point regarding the slight weight difference of using 32H instead of 24H
well your 2.2's will certainly look interesting on those...
I'd stay with 32H, the weight savings are minimal and the benefits significant.
YMMV, I find my Aplha 340s pretty weak, and that's on the road, maybe I need to up the tension.
Is there any way you can build up a laterally stiffer wheel with a SP dynamo hub?
The actual body of the SP hub is the same design for 74mm wide Brompton version and the 100mm wide road/mtb version.
You are basically running a 74mm wide hub with axle end spacers. That's why it has such narrow flanges.
It's fine on my commuter, in fact the flex makes it a little more comfy.
Whether it's too flexy or not for MTB I don't know... probably not the ideal hub to pair with 35mm wide carbon enduro rims
If you're going for new forks anyway, why not Boost and a SON dynamo?
This is more than likely the reason for the flexy feel of the front wheel. I will have a look at the SON, but a Boost fork will make no diffference to lateral stiffness if the flange width is still narrow.You are basically running a 74mm wide hub with axle end spacers. That's why it has such narrow flanges.
Good or bad way?well your 2.2's will certainly look interesting on those...
I'm pretty sure the SON is a 'proper' Boost hub.
hey ho. I have just purchased a set of RS Pikes off ebay that are non Boost so will have to go with a standard 100/15 setup.I'm pretty sure the SON is a 'proper' Boost hub.
Just looked at the SON spec and the 100/15 hub has a 47.5mm centre of flange spacing and the SP has a 50mm to outer edge of flange spacing.
Given that, I suspect lateral stiffness will be the same?
If I go for a carbon rim can I have higher spoke tension than an aluminium rim to help lateral stifness and the fact the hub is narrow?
Do the pikes do torque caps? If so get the SRAM hub (unless you can't) as the caps make a difference to stiffness.
'Now given I currently use my 29er for both XC riding and bikepacking I am rather confused regarding the correct rim width, spoke count and benefits of carbon fibre vs aluminium on MTB wheels.
So what level of lateral stiffness do you need? 4 or 7?
None of the dynamo hubs will have torque caps Mike.
This sounds like a pretty beefy build for bikepacking.
If I go for a carbon rim can I have higher spoke tension than an aluminium rim to help lateral stifness and the fact the hub is narrow?
It will help very little. From the link above
"Within a ‘normal’ range of spoke tension, wheel stiffness is unaffected. "
You could..
- Ditch the pike and use a QR fork and Shimano dyno hub (stiffest setup IMO)
- Run 26" wheels!
- Stop worrying about the flex.
- Ditch the dyno and use some battery lights and power pack. If you get one with Qualcomm quick charge input, 1 hour charging the battery in a cafe is going to equate to 8 hours (ish) charging it while cycling (12v/2a vs 5v/0.5a)! Hardly worth bothering with USB dyno charging!
https://www.amazon.co.uk/Upgraded-RAVPower-20100mAh-Portable-Technology/dp/B01CHZMFUS
One that ensures that my front wheel feels like it is linked to my handlebars. On my last bikepacking trip and when climbing out the saddle it felt very much like it wasn't. Could have been the Fox float 32s, 1 1/8" steerer, QR front axle, wheel that caused it, but I want to get the front end much stiffer.So what level of lateral stiffness do you need? 4 or 7?
Also replacing stock cube syntace stem and bars with Thomson Elite and Easton bars.
I agree, and although I want stiffness I don't want it super heavy so I am trying to strike a compromise.This sounds like a pretty beefy build for bikepacking.
It's a shame I cannot replace the QR 1 1/8" 32 Floats with the 15mm tapered Pikes I have ordered and use the QR wheel to see whether it was the forks that made the front feel noodly. The SP-D QR hub I have cannot be changed to 15mm so I'll have to suck it and see and just hope it does solve the problem.
As to the wheels, I think the comments on here have persudaded me that fat enduro rims are overkill. I will just stick with a higher spoke count.
I know we shouldn't all just follow like sheep (and I've been known to "go my own way" at times too) but a quick look at other folks bikepacking bikes would show very few going to such extremes in order to remove this perceived flexing. It should at least give you a little pause for thought?
Fair point, but you'll have to trust my judgement when I say the front end of the bike was far too flexy. I suspect in all honesty that it was the forks. 29er 32 Floats are apparently well known for flexing. When I braked they axle of the front wheel would move back a long way and occasionally rub on my jetboil stove bag mounted under the down tube.I know we shouldn't all just follow like sheep (and I've been known to "go my own way" at times too) but a quick look at other folks bikepacking bikes would show very few going to such extremes in order to remove this perceived flexing. It should at least give you a little pause for thought?