What Middleburns do I have and what spindle length do I need?

[Edav97]

Hi all,

I’ve got some Middleburn cranks I’m using for a 1x drivetrain and just trying to figure out what spindle length I need for my bottom bracket. I’m not 100% which model these are? I thought RS7s but even with that info information online about spindle length varies from 103-118mm…

Any I for would be great!

 

[bold stelvis]

I have the same cranks - so pretty sure they are RS7s though mine are isis rather than square taper

pretty sure my BB spindle is around 115mm - but I could be out by a few mm (it doesn't say on it) - and I guess square taper might be different from isis anyway - sorry not much help!

If I were to guess I would just pick whatever the shimano standard was for sqr taper triples back in the day - likely to be similar I think?

 

[ishaw]

I think it's usually 113mm.

 

[FluffyChicken]

From RS7 as it is linked to ISIS it'll be 113mm for a normal triple setup, and 118mm for the wider (or DH) 50mm setup.

 

[FluffyChicken]

I guess 108mm could be used if you wanted to move to a double using the triple spider and centre it better., though also bringing the arms in more.

 

[Edav97]

I guess 108mm could be used if you wanted to move to a double using the triple spider and centre it better., though also bringing the arms in more.

thanks for your comment!

The spider on this is a double. And I’m planning on using it with a single chainring for a 1x set up. I may just have to order a few and see what works…

 

[FluffyChicken]

I would start at 113 then, the double spider I hope is adjusted so the centre of the two rings is now where the middle ring teeth would be so the crank can still be in it proper position,

 

[Mace4130]

I use 113mm on both sets of my Rs7’s. One 1X and the other a triple. A 107 would give me a perfect chain line on the 1X I think.

 

[Woz]

Ditto with all the above. They are RS7 and they recommended 113mm JIS.

103mm will only practically work with a DS cup that is internal in the shell (ie. no shoulder). 107mm is generally possible.

Worth noting, that - at least in my experience - the generation of triple spiders and DUO spider 94 BCD was not the same chain line. The DUO was pushed more outboard by about 2mm presumably for more DH use with more modern suspension frames and wider tyres.

 

[Edav97]

Thanks for all the responses! I’ve found several sources stating 113mm now too so think I’ll start out with that and see how it looks.

Much appreciated