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I'm looking at swapping the 32T chainring (Race face turbine cinch crank) on my YT Jeffsy for a 30T one. Superstar look the cheapeast and offer either a 0mm offset or a 3mm offset but I have no idea which is right.
The Jeffsy has a Boost rear and I've emailed YT and all they could tell me is that the bike has a 52mm chainline, but I'm not sure how this ties up with the Superstar offsets.
Anyone out there done the same or is able to expand on my woeful knowledge of offsets and chainlines?!
Ok, I've done what you are doing on a Jeffrey....
If the frame is carbon you need a proper boost chain ring. I got the AbsoluteBlack one. For a carbon frame you need Boost as said, so 3 mm offset.... or the ring is VERY close to the frame.
If alloy frame you *should* be ok with a non boost ring as the clearance is better.
Hope that begins buddy. I spent a long time on this issue so I'm petty sure my info is right.
Edit: All above is based on the RF crack being a non boost crank. Therefore a standard offset is 6 mm. Boost is 3 mm. Not sure what the SS zero mm ring is all about.... But I'm sure it would destroy your chain line!
Be aware, the boost ring will make your chain line worse. It's the price you pay for Boost. If your frame is alloy and you fit a standard ring, your chain line is much better. Carbon, you need boost im afraid.
Ok cheers for the info there, similar setup to mine except I've got the Alu jeffsy. Superstar state the below so sounds like the opposite of what you said about 3mm being Boost?
- Standard ring = 3mm offset
- BOOST ring = 0mm offset
oh changed my chainring twice on my carbon Jeffery and not even considered this. Runs to shed to check back in 5
I think SS are talking about rings to fit a Boost crackset perhaps though I'm not certain?
Your crankset is very likely not Boost.
If you really want to buy from Ss go for the 3 mm ring in my opinion. The zero will result in a terrible chain line.
All above assumes you have a *non* boost RF crank. To my knowledge jeffsys come with a non boost crank.
YMMV 😉
Just measured the original Race Face one and the Blackspire Snaggletooth non-boost one and the measure up near enough the sam. I layed them flat on the bench cup side down and they measure 7.5mm with a thickness of 4.5mm so would mean a 3mm offset ???
I now have fitted a Works oval 30t, again non boost . Works great.
Ok cheers all, I'm not sure I'm any the wiser but will order a non boost jobby and see how it looks. Why did bikes go all complicated?!
The complication is the cranks can be boost and/or the chaining can too.lol
I should point out that my 30T was an oval.... Therefore going upto a 32T at it's widest.... Which is when the clearance between it and my carbon jeffsy's chain stay was uncomfortably close with the non Boost ring. Went to the Boost oval and clearance was not a worry then. The clearance is tighter on the carbon chain stay.
Much of the confusion is caused by chain rings or chai sets being described as having offset which implies that the movement is away from the frame when in fact a 3mm offset moves things 3mm closer to the frame .
Yep, 3mm being boost, 6mms being nearer the frame and non boost.
I think I now or less have my head around it these days (until I come you up against a boost crank set...) but it's ironic that it makes the chain line worse, but that's progress innit. 😃
My shimano xt boost crankset has the boost element built into the crank. Others have the boost element as part of the chainring.
Superstar non boost was the correct replacement, thanks all
Glad you got it sorted mate. I had to prefe 2 before I got it right.
I've also now gone the opposite way to you, from 30T to 32T but it's an oval, so I'm letting my knees and legs cheat a bit. 😉