Just reading an article in pinkbike and saw this photo with comments about the rider only running 4 rotor bolts. I know it’s been going on for years even in dh but I’m just curious how the governing bodies allow it. Surely if something is designed by the manufacturer to have 6 bolts they should use 6 bolts. I know they have no warranty to worry about, weigh less and brake less than us mere mortals and the hubs are obviously strong enough but surely the powers that be would stop anyone doing it therefore removing any advantage.

http://m.pinkbike.com/photo/12259824/

I’m just curious.

steve peats been doing it for years

his santa cruz

and the front

And it hasn’t even got two fork legs! OMG!!!!11!!!1!!!

I’m doing it on the back coz I lost one and running four seemed better than five…

sod weight saving there, thats like the last of the last places to save weight,

i chucked all my ti bolts in the bin and went back to using steel for callipers and rotors as i got sick of ti ones rounding off

Oh, give over about the weight saving ! Ti disc bolts are barely over a gram each. So you’re saving maybe 5g off a 15kg (?) bike by running four bolts per disc. Nobody could possibly notice the difference.

So it’s purely psychological, either for your own benefit, or to scare the competition about how obsessed you are.

So it’s purely psychological, either for your own benefit, or to scare the competition about how obsessed you are.

But if you apply the same obsessiveness to the complete bike, it could result in an overall weight saving that may make a difference.

It was peaty I was thinking about when I wrote about them doing it dh.

Why remove weight if you’re going DOWN the hill?

F = MASS * acceleration

F = MASS * acceleration

You also need to pedal a DH race bike, fast, and accelerate out of corners, so Acceleration = F/m

That’s Peaty’s world champs bike, I don’t think he normally ran it like that. Other highlights included bearings with the rubber seals taken out to reduce drag. I think at that level it’s probably as much about believing your bike is faster.

That lefty one is weird, since it’s got uneven bolt spacing- if I saw that, I’d assume a bolt had dropped out tbh

If I were going to omit bolts to save weight, I’d grind off the lug on the rotor as well. Or get some custom rotors that take the load directly back to the bolts I’m using.

I wonder if missing bolts make much different to the heat conduction out of the rotor?

This might show my age but the old Rock shox discs used to have only 3 bolt rotors as standard ( white ind hubs )
Mostly fitted to gt lobo and sts dh bikes

But must agree with Ti bolts the weight saving is tiny

Oh and hope still use 3 and 4 bolt discs and hubs on there wheels

I removed all my rotor bolts, you should see how fast it went downhill 😯

Oh and hope still use 3 and 4 bolt discs and hubs on there wheels

Not in the last 5 years they haven’t, besides. they were chainring sized bolts specifically designed for the purpose.

disc rotor bolts is the last place I’d choose to save weight, I run Ti bolts and they weigh a gram each so as mentioned before, about 6 grammes max lost. stupidity.

I’m running 5 bolts on my SS rear disc. When the decking squirrels get tired of playing with the other one they’ll throw it back on the patio and I’ll continue refitting it.
Note to self: buy Park Tools magnetic bits tray to avoid this reoccurring.

So it’s purely psychological, either for your own benefit, or to scare the competition about how obsessed you are.

At ironhorse Sam Hills mechanic used to put foam in the frame to dull any noises, as it gave Hill more confidence and made him faster.

I probably check my rotor bolts every 6 months, if that. so I am not going to do it, but if you have a mechanic checking your bike every day its a bit different.

I was unaware hope had stopped doing xc3 and am4 wheels. But yes there were a little bigger

That lefty one is weird, since it’s got uneven bolt spacing- if I saw that, I’d assume a bolt had dropped out tbh

POSTED 21 HOURS AGO #

Surely the whole point of that picture is that there is a bolt missing .Presumably he’s running 4 bolts on a 6 bolt rotor .

Better off to cut them in half. What is the part of the bolt doing when its in free air?
So long as you measure them so they are flush with the hub wayy hey with a junior hacksaw, dab of loctite and your sorted .
Never understood why they need to be as long as they are .

insert st stw disclaimer here.-

IANAE

I always thought this was a bit ridiculous, even on Peaty’s World Champs bike.

Then you remember that he won that World Champs by 0.05s.

Maybe there’s something in that level of OCD.

Saving 6g on every component on a bike adds up quick. 6g off each of 17 components is over (albeit just) 100g saved. 100g is reasonably substantial. Save 100g 5 times and thats half a bag of sugar or half a litre of water that you don’t have to push when pedalling up to speed. The extra mass when descending only increases momentum, not speed, and all extra momentum really does is give your brakes a harder time when you have to slow for a corner.
Saving weight is worth it, unless you’re sacrificing strength, which in this case the minor strength decrease clearly doesn’t matter.

Peaty allegedly uses Matrix pads, which have no friction co efficient, so he could use 2 bolts without any dramas. My old Hopes , used to have a splined spider centre and 3 bolts holding the disc to the spider. This was their Mk1 version of the hydraulic disc systems, then they went to 5 bolts. I managed to pull the bolts out the disc and had to re engineer with longer bolts and nylocs on the back, even though Hope said I cant have done it and then they made a 5 bolted version. They are obviously never wrong 🙄
I bought some Ti bolts for a lightweight build and looked scared in fitting them, so refitted steel ones and use the Ti ones for bottle cage blanking bolts.
As for the probable Team Cannondale bike above, that lefty plastic cover on the leg is held on by 3 bolts and is a lump of plastic and for a team bike getting stone damage on the stantion is not an issue, just fit a new fork and taking it off will save more than the bolts on the disc.
The hubs could be redesigned in having a locating pin sticking out of 2 bolt holes and then fitting 4 bolts on Peatys bike, but as everyone says, the weight saving especially at the hub, is about the same as a bogey clearout before riding.

Better off cutting your hair and having a p£&s….