Cross-Chaining on a BSSHD with 9-Speed Rear

[aaronm]

Hi All,

I build my son a bike using a BSSHD and a 9-speed rear cassette and it's cross chaining quite a bit in anything below 5th gear (the bigger sprockets are lower) so down in 1st-4th it gets progressively worse. I'm using the Luna cycle BSSHD kit with the optional chain ring they sell to go with it.

Here are some options:
Shave the bottom bracket to push it all over a little. I might be able to get 1/8 inch or so.
Will look at the plain (ugly) Bafang stock chain ring. I think that will get me a 1/8 inch or so.

Moving the center 1/4 - 3/8 inch inward maybe helps but really doesn't make the universe a great place.

I was considering getting a spare cassette or two, mixing up the pieces a little and make a cassette like 21-23-24-26-28-30-32-34-36 which is about $60 and fairly easy. It will not necessary solve the cross chaining, but it will shift the gears considerably to right, which will allow him to stay in 7-9th gear for most of the time, which is straight and only need the lower gears occasionally. It will put quite a bit less stress on the chain IMO. Not really solve the problem, more like avoid the problem.

Of course he's not to thrilled with losing the 12-20 sprockets in the rear, but really 35MPH is too fast on a bike. I took it for a test ride and it's really spooky, anything above 25MPH says "future victim" on it. I pay for the bike and health insurance so my rules win.

I was hoping someone else out there had some really cool idea that I wasn't thinking about.

Maybe a way to inset the chain ring. The BSSHD has the space where the gear case is, it's about 1 inch wide??? Is there anything that I can buy without having to custom fab something?

Thanks
Aaron

 

[dustNbone]

I would start with a new chain and cassette, and make sure the derailleur is running true. I had similar problems on my BBS02 when I first installed it, but in the higher gears. Previous to the installation, I used those gears far more often than the lower ones. I first tried changing just the chain, and it got alot better but still those 2 gears (5th and 6th of 8 ) would slip on me under hard load. New cassette and it's been solid for over 3,000 miles now.

I'm actually using the stock 46T Bafang chain ring, I had considered the 42T Bling Ring as a solution but I never needed it. Once I got everything dialed in chain derailment and slipping issues seemed to disappear.

 

[Overclocker]

yeah the chainline sucks so this is how i do it.

i'm using 8spd shifters because the larger cog-to-cog spacing makes it more tolerant of misadjustment. these are various cogs from 9spd cassettes but spaced out with the proper 8spd spacers. i got 2 dummy cogs on the left to bring the granny outboard to get a better chainline. then i locked out the smallest cog using the limit screw.

so this is effectively a 5spd cassette which is really all a bbs02 needs. but since i'm on the 44t chainring i need to add a 42t to this cluster...

 

[aaronm]

Thanks,

That is so cool with moving the good gears to the middle/outside. I though about it but didn't know how it would work in practice, I figured the chain would jump off the back and all heck would break lose.

I think that is the winner. Cheap and effective.

I would like also to thank Mr DustNbone, but the problem here is everything is new to start, so wear was not a factor.

Thanks