[Nick]

wouldn't that result in a stronger wheel build? I know, pressing questions for 2025 from a 27.5 holdout.
In theory, would larger diameter flanges result in a stronger wheel due to shorter length spokes?

 

[Toshi]

hub motors have large flanges

<ducks>

anyway, flange lateral spacing is certainly a consideration. thus Super Boost Plus and all that. this is also part of the reasoning (with availability/what was on sale the other bit) of why my commuter bike with 29" rims has 150 mm fat bike spacing up front. strongest wheel possible.

 

[Westy]

I don't think larger flange diameters give you much of a strength to weight advantage and I haven't heard of anyone having any issues with torsional rigidity. Spoke count and lacing options probably provide better benefits.

Flange spacing certainly increases with boost for better side to side rigidity.

Wider rims also arrived with 29 dominance. Old narrow rims on 29" wheels were sooper noodly.

If you are a fan of nipple twisting and have built up a modern wheel, you can get a better feel of how a modern 29" wheel feels. I didn't have a point there, I just wanted to say nipple twisting.

 

[englertracing]

Flange width effects bracing angle more than diameter
Flange widths have grown for example boost and super boost
Widest are asymmetrical hubs to be paired with asym rims.

 

[Nick]

My trail and dh bikes are 157 super boost and only 27.5. Perhaps that why I perceive such a flex difference in typical 148 boost 29” setups ?

 

[Toshi]

could be your Hulk-strength

 

[jonKranked]

don't some of the dinner plate cassettes have the largest cog set inboard from the back of the freehub interface? if that's the case, i could see larger diameter drive side flanges creating interference with the spokes and the largest cassette cog.

 

[Westy]

My trail and dh bikes are 157 super boost and only 27.5. Perhaps that why I perceive such a flex difference in typical 148 boost 29” setups ?

Over the last 4 years or so I have played around with wheel rigidity a bit on the rear wheel of my hardtails. Although this did not include different hub widths and I was looking for vertical compliance. The two extremes being a 27.5” 32 spoke wheel with wide carbon rims and a 29” wheel with 28 spokes and medium width rim made of some cheese alloy.



There are a lot of variables in how ‘rigid’ a bike feels and for the most part what I felt the wheel was a rather small part of it. Tires, pressure and ultimately the frames made a much bigger difference. My two hardtails are also at different extremes. The Chromag being very very stiff and the RSD having a very flexy rear end. It didn’t matter if I had a rigid wheel or not, over fast chunky shit the RSD just didn’t track well while the Chromag was still kind of harsh yet still very precise.



All that to say I think anything you felt was just as likely to come from the frame as anything else. I guess tunable rigidity is becoming the next big thing in world cup DH, which makes sense. Frame rigidity has been a well known variable in Moto GP for decades. When a bike is leaned over bumps are not inline with suspension so frame deformation becomes the suspension. Stiffest is not always the best, there is a Goldilocks zone and that will also depend on the rider.

 

[Nick]

All that to say I think anything you felt was just as likely to come from the frame as anything else

Agree. My frame is a plastic Pivot Mach 6 and it's quite stiff laterally, IMO, at least compared to several friend's frames. My initial question was more from a "I want the strongest 32/3x wheel build I can have" by shortening the spoke lengths between flange and rim as much as possible.

*flex story time* I sold a set of these fancy pants brakes to a friend who ended up with inconsistent bite point, lever going to the bar, scary rides, etc. I bled them twice for him, no issues. Happens again. I was consistently able to grab his rear wheel with my hand and flex it so much the rotor was pushing in the brake pistons, requiring a reset pull before engaging. I chalked it up to a combo of rear triangle, rear hub excessive flex, and the caliper piston seals having very very low friction. Those brakes themselves were and are still working perfectly.

 

[Westy]

Agree. My frame is a plastic Pivot Mach 6 and it's quite stiff laterally, IMO, at least compared to several friend's frames. My initial question was more from a "I want the strongest 32/3x wheel build I can have" by shortening the spoke lengths between flange and rim as much as possible.

*flex story time* I sold a set of these fancy pants brakes to a friend who ended up with inconsistent bite point, lever going to the bar, scary rides, etc. I bled them twice for him, no issues. Happens again. I was consistently able to grab his rear wheel with my hand and flex it so much the rotor was pushing in the brake pistons, requiring a reset pull before engaging. I chalked it up to a combo of rear triangle, rear hub excessive flex, and the caliper piston seals having very very low friction. Those brakes themselves were and are still working perfectly.

It is worth noting that stiffness and strength are not the same and often mutually exclusive. Wheels can absorb impacts because they can distribute the load across multiple spokes. A wheel with stiffer spokes will have higher individual spoke loads, so stiffer but all else being equal not as strong or durable. In my head this makes sense from an engineering perspective and I think it is generally accepted that double butted spokes will make for a stronger wheel than straight ones despite theoretically being weaker. Doesn't hurt that spokes also tend to break either at the nipple or the j-bend. Spokes also tend to fail because of fatigue failure and for complex reasons a longer less stiff spoke will have a better fatigue life.

Rigid rims will do a better job of distributing loads across multiple spokes while providing a stiffer feel. IME the best combination of stiffness and durability is a wide but short rim cross section with relatively compliant but strong double butted spokes like Sapim CX-Rays. It helps that cold working the blade shape actually makes them stronger. But rider style and ultimately speed has a lot to do with it.

 

[OGRipper]

Reach out to e.thirteen and tell them the Chub Hub was before its time.

 

[buckoW]

Reach out to e.thirteen and tell them the Chub Hub was before its time.




View attachment 224404

I built one of those up recently.

 

[englertracing]

Agree. My frame is a plastic Pivot Mach 6 and it's quite stiff laterally, IMO, at least compared to several friend's frames. My initial question was more from a "I want the strongest 32/3x wheel build I can have" by shortening the spoke lengths between flange and rim as much as possible.

*flex story time* I sold a set of these fancy pants brakes to a friend who ended up with inconsistent bite point, lever going to the bar, scary rides, etc. I bled them twice for him, no issues. Happens again. I was consistently able to grab his rear wheel with my hand and flex it so much the rotor was pushing in the brake pistons, requiring a reset pull before engaging. I chalked it up to a combo of rear triangle, rear hub excessive flex, and the caliper piston seals having very very low friction. Those brakes themselves were and are still working perfectly.

wheel stuff if you want to nerd out

bicyclewheel.info

bicyclewheel.info

bicyclewheel.info

Wheel Stiffness Test

Measurements of the lateral stiffness of many bicycle wheels

www.sheldonbrown.com

.

Wheel Deflection Test Results Table

 

[dump]

Over the last 4 years or so I have played around with wheel rigidity a bit on the rear wheel of my hardtails. Although this did not include different hub widths and I was looking for vertical compliance. The two extremes being a 27.5” 32 spoke wheel with wide carbon rims and a 29” wheel with 28 spokes and medium width rim made of some cheese alloy.



There are a lot of variables in how ‘rigid’ a bike feels and for the most part what I felt the wheel was a rather small part of it. Tires, pressure and ultimately the frames made a much bigger difference. My two hardtails are also at different extremes. The Chromag being very very stiff and the RSD having a very flexy rear end. It didn’t matter if I had a rigid wheel or not, over fast chunky shit the RSD just didn’t track well while the Chromag was still kind of harsh yet still very precise.



All that to say I think anything you felt was just as likely to come from the frame as anything else. I guess tunable rigidity is becoming the next big thing in world cup DH, which makes sense. Frame rigidity has been a well known variable in Moto GP for decades. When a bike is leaned over bumps are not inline with suspension so frame deformation becomes the suspension. Stiffest is not always the best, there is a Goldilocks zone and that will also depend on the rider.

My evil sovereigns are stiff as hell. The stays are massive and extra thick for grinding street rails and crap. The 31.6 seat tube doesn’t help with much flex either. Tuning in some flex would be amazing.

 

[canadmos]

Is a good compromise a mixed wheel bike?

I don't notice anything funky on my mixed wheel Banshee Titan. Front wheel feels fine in the Zeb and the back wheel just get pummeled like normal. Usually it's the back wheel that suffers...