awer1

i have a sugino 75 bb with a 103mm spindle. but my chainline is wack by about 4mm. i have rpm track cranks that give me a 46mm chain line my bontrager track wheel is 42mm. ive read a few things about rpm cranks having a strange dish and giving a 46mm chain line perhaps someone can confirm this. can i solve this by getting something like a sugino sd or 75 crank. cheers.

jussik

Whoa, you have a Bob Jackson hanging on the wall!

But to comment on your question, RPM cranks are obviously wack.
But have you changed the spindle in your bb? The real Sugino 75 bb axle should be 109mm.

awer1

aah fu(k me your right. so will sugino 75s give me the magic 42mm chainline? or something a bit cheaper - maybe ill sell the bob jackson!

frankstoneline

you said it has a 103 spindle in it and it's still giving you a 46 chainline? oof, thats rough. I would say look into a different set of cranks, sugino RD's will work with your 103 bottom bracket, and I like the ones i have. They arent really fancy but they get the job done on a budget.

dervish

dont sell the bob jackson!

awer1

nah i was wrong my spidle is 9mm. i didn't measure it accurately and when i checked on line i was looking at the wrong bb info.

https://www.outspokencycles.co.uk/product_info.php/cPath/40_43/products_id/95[/URL]

but i dont really want to replace the sugino 75 bb just for the sake of some crappy cranks well perhaps functional is a better word. so what cranks give a 42mm chainline on a 109mm bb? i hear grand mighty and sugino do but i cant find confirmation.

the bob jackson is a tiny bit to big for me so it might be sold at some point but only so i can put the money towards one of their off the pegs.

jussik

Well, this might not help you much but Dura-Ace 7600 square taper cranks will give you that perfect chainline, just like Sugino 75s will.

And I also had a pair of old Sugino Mighty road cranks on my bike with the sugino 75 BB and the chainline was fine, even with the chainring on the outer position.

sp00ki

wat

awer1

what?

thequickfix

I am a bit confused by your stream of consciousness type postings, but I think you are saying that you have the 109mm sugino 75 bottom bracket and you're using RPM track cranks? As far as I know, sugino 75 cranks are the only cranks that use a 109mm ISO BB spindle (except some Italian road doubles, probably). I have no personal experience with the RPM cranks, but it seems like you would need a 103mm JIS spindle to put them in the right place. I don't think there's anything wrong with the "dish" of the cranks, the problem is that they are not compatible with your BB.

Basically, it seems like your options are to switch the cranks to 75s or switch the bottom bracket to 103mm.

el cheapo

+1 to thequickfix's sound advice.

I ride Sugino SDs and they're just fine. IMHO 75s are not worth the huge cash difference. I'd sell ur 75 bb off as well and get a Shimano sealed cartridge but thats just me.

If you r gonna part wit the B Jackson, I'd be way interested if it'd fit me. I'm 6'.