Stories posted under Pinkbike Community blogs are not edited, vetted, or approved by the Pinkbike editorial team. These are stories from Pinkbike users.
If a blog post is offensive or violates the Terms of Services, please report the blog to Community moderators.
Bigger=Stronger ? Calling BS on Super Boost
The Knolly guy is going to call me an Armchair Engineer but I'm going to go for it. I might be barred for life at Knolly bikes for critical thinking.
After this article about super boost 157 I grew tired of the argument of "it's wider so it's stronger" which is the main selling point of Boost 148 and SB157.
Making something bigger to make it stronger is level 0 of engineering. Prehistoric Humans already knew the trick when choosing the right bludgeon for mammoth hunting. Even Sram though of it when releasing DUB.
![photo]()
The premises are true : larger hub equals flatter spoke angle. Let's do some quick maths.
My hypothesis is : you want to approach the maximum tension allowed by the rim on the drive side (F2) to reach maximum strength. The resulting axial force (T2) must be balanced on the non-drive side (T1) resulting in a tension F1.
![drawing of a hub]()
With the above drawing with a2 going longer, you get a bigger axial force T2 for the same tension. That is the desired effect since T2 will impact directly your wheels' lateral flexibility.
Here is a spreadsheet, detailing the maths for 27.5" and 29" wheels. No rocket science here, just geometry. Feel free to correct if I made mistakes.
![maths crap]()
And the results :
![axial strength gain over 142 hub]()
![tension difference]()
SB157 isn't any stronger than 157DH but results in more uneven wheel. Boost 148 barely improved anything.
Even tension is more important to me since it impacts directly on durability. I'm not the first one to talk about this :
![American Classic 2017]()
Building strong wheels was never a problem, but they tried to solve it nontheless. And with it cames load of crap : plus tyres, crappy chainline, heel rub, chainring limitations. The goal was to have both short chainstays and 2.8 tyres, too bad I want none of them. Really short chainstays are only good if you're a front charging rider, give sharp handling but require precise body balance.
What would be other ways to go ?
One is offset rims, WTB is the brand that come to my mind about this. Another one is non symmetrical stays, which has been tried already.
Super Boost 157 reminds me of Spinal Tap :
At least I'm ok with one thing in the Knolly pie chart :
After this article about super boost 157 I grew tired of the argument of "it's wider so it's stronger" which is the main selling point of Boost 148 and SB157.
Making something bigger to make it stronger is level 0 of engineering. Prehistoric Humans already knew the trick when choosing the right bludgeon for mammoth hunting. Even Sram though of it when releasing DUB.
Putting my life in danger, riding non boost wheels
The premises are true : larger hub equals flatter spoke angle. Let's do some quick maths.
My hypothesis is : you want to approach the maximum tension allowed by the rim on the drive side (F2) to reach maximum strength. The resulting axial force (T2) must be balanced on the non-drive side (T1) resulting in a tension F1.
my crappy schematisation of a hub
With the above drawing with a2 going longer, you get a bigger axial force T2 for the same tension. That is the desired effect since T2 will impact directly your wheels' lateral flexibility.
Here is a spreadsheet, detailing the maths for 27.5" and 29" wheels. No rocket science here, just geometry. Feel free to correct if I made mistakes.
And the results :
Both 157 hubs improve lateral strength, Boost 148 doesn't improve much
Tension imbalance gets worse with SB157
SB157 isn't any stronger than 157DH but results in more uneven wheel. Boost 148 barely improved anything.
Even tension is more important to me since it impacts directly on durability. I'm not the first one to talk about this :
Bill shook didn't use all the free space but balanced the spacing instead
Building strong wheels was never a problem, but they tried to solve it nontheless. And with it cames load of crap : plus tyres, crappy chainline, heel rub, chainring limitations. The goal was to have both short chainstays and 2.8 tyres, too bad I want none of them. Really short chainstays are only good if you're a front charging rider, give sharp handling but require precise body balance.
What would be other ways to go ?
One is offset rims, WTB is the brand that come to my mind about this. Another one is non symmetrical stays, which has been tried already.
Super Boost 157 reminds me of Spinal Tap :
 | Well, it's one louder, isn't it? It's not ten. You see, most blokes, you know, will be playing at ten. You're on ten here, all the way up, all the way up, all the way up, you're on ten on your guitar. Where can you go from there? Where? |
At least I'm ok with one thing in the Knolly pie chart :
Author Info:
Member since Nov 1, 2014
Must Read This Week
Going back to the original discussion where you directed me to this blog, I'd be interested to hear your views on the bit where you state "My hypothesis is : you want to approach the maximum tension allowed by the rim on the drive side (F2) to reach maximum strength." You seem like a smart guy, and you have the maths. I'm sadly ill equipped in that dept