BB30 vs GXP

[Quagga]

Does anyone know the spindle length for BB30 (i know there are two) and for GXP

 

And also what is the chaining offset for each

 

I have done a search but could not find it.

[JA-Q001]

MTB or road?

[Quagga]

MTB

[DieselnDust]

Does anyone know the spindle length for BB30 (i know there are two) and for GXP

 

And also what is the chaining offset for each

 

I have done a search but could not find it.

 

 

Difficult question to answer without the bb shell width and crank that you want to fit as each design will have a different thickness of crank arm and therefore the axle length will vary.

[Quagga]

Difficult question to answer without the bb shell width and crank that you want to fit as each design will have a different thickness of crank arm and therefore the axle length will vary.

Sorry should have said for cranks

 

For example BB30 cranks comes in two lengths 101.5mm and 95mm

But what is the GXP MTB crank spindle length

and what is the DUB MTB spindle lenght 

 

Edited July 17, 2020 by Quagga

[JA-Q001]

This is a good guide:

 

https://wheelsmfg.com/crankset-tech

[Quagga]

This is a good guide:

 

https://wheelsmfg.com/crankset-tech

It does not give spindle length on Diameter

[JA-Q001]

https://www.enduroforkseals.com/products/bottom-brackets/

 

Ok, this one does give actual axle lengths.

[DieselnDust]

Generally the short axle is for road and the long axle is for mtb. Some mtb manufactures used the road spindles on mtb cranks. I believe it was Specialized with the OSBB.

Most other mtbs used the 101.50mm spindle. Cannondale uses 137 mm for Ai 125 mm for older mtbs.

SRAM DUB I believe is around 127 mm so caters for 9 lot of bb spindle length requirements. Will need to confirm that number

[Quagga]

https://www.enduroforkseals.com/products/bottom-brackets/

 

Ok, this one does give actual axle lengths.

Thank you, I now now the DUB is 100mm

GXP is not listed however

[JA-Q001]

Ill check if I can measure one for you. Just have to see if I have a MTB one.

[Quagga]

Ill check if I can measure one for you. Just have to see if I have a MTB one.

Thank you 

 

I just want to work out what chaining goes with GXP and which one with dub

6mm with dub ?

[JA-Q001]

If I am correct, SRAM DUB and GXP use the same offset, 6mm. Narrow BB30 can use 3mm or 0mm, depending on BB width and crank type.

 

if you have a boost frame, you would use the 3mm on the DUB/GXP.

 

This is to my understanding (at the moment) and it can differ from manufacturer to manufacturer. 

[Quagga]

If I am correct, SRAM DUB and GXP use the same offset, 6mm. Narrow BB30 can use 3mm or 0mm, depending on BB width and crank type.

 

if you have a boost frame, you would use the 3mm on the DUB/GXP.

 

This is to my understanding (at the moment) and it can differ from manufacturer to manufacturer. 

Perfect thank you

 

Is this the same for boost frames?

[DieselnDust]

If I am correct, SRAM DUB and GXP use the same offset, 6mm. Narrow BB30 can use 3mm or 0mm, depending on BB width and crank type.

 

if you have a boost frame, you would use the 3mm on the DUB/GXP.

 

This is to my understanding (at the moment) and it can differ from manufacturer to manufacturer.

 

This is why I asked him to be more specific.

The correct chainring to use is not so clear cut as long axle equals x offset.

one needs to consider the frame and chain line.

generally boost bikes use a 3mm offset. Sometimes a 0mm offset if the offset is built into the cranks

or even the frame e.g. Cannondale Ai and Pyga Stage.

But if it's a 104BCD Crank then we need to know which Crank and chain ring he wants to use.

so if we know the

bike brand and model

bb shell width

And rear axle dropout spacing its easier to advice.

But I feel like I'm a supplier to a skunk works project

[Quagga]

This is why I asked him to be more specific.

The correct chainring to use is not so clear cut as long axle equals x offset.

one needs to consider the frame and chain line.

generally boost bikes use a 3mm offset. Sometimes a 0mm offset if the offset is built into the cranks

or even the frame e.g. Cannondale Ai and Pyga Stage.

But if it's a 104BCD Crank then we need to know which Crank and chain ring he wants to use.

so if we know the

bike brand and model

bb shell width

And rear axle dropout spacing its easier to advice.

But I feel like I'm a supplier to a skunk works project

Sorry. I have not been clear.

 

We want to take gxp crank off a spez and fit dub.

Can we use current chainring

 

Then we thought going bb30 will chainring work on that.

 

Bottom line is. Friend has gxp on boost spez 2018.

Can he go dub without a new chainring or even bb30?

He wants to keep chainring saving him R1k eish