Shinkers

Hey,


Has anybody had any success running 1x7 with a large chainring and shortening the spindle a bit?


I've tried 1x10 before and it was a complete failure since I'd drop my chain as soon as I pedaled backwards on either end of the cassette. I've got a bottom bracket that splits the chainline on a regular double and I'm thinking the chainline on a 7 speed would be less extreme so it may work better. Gearing would be a 53t chainring with a 13-23 cassette.


I've got everything to go 2x but got to thinking that I may dig 1x for a bike that won't see any hills. On my Trek, I only use my 39t for climbing.


Thanks for any info.

fietsbob

On the cheap, put a FD Back on and run the L limit screw in , to center it over the chain, no cable attached..

& how about.. don't use a chainring from a STI crank, use full height tooth chainrings for single speeds
(I have that on my IGH bike with a chain tensioner..)

there are chain keepers that do that too... K edge one US maker https://k-edge.com/product-category/chain-catchers/



1 by you center the chain ring on the chain line aligned with #3 of 7...









.....

HTupolev

Most chainrings are designed to allow the chain to derail easily. If you want to use 1x, use a retention mechanism of some sort, and/or get a narrow-wide chainring whose tooth profiling grabs the chain better.

fietsbob

Or, this being C&V, get old chainrings from before the index shifting thing became dominant..

I have steel chainrings from BITD on a couple bikes, they last a very long time..

Shinkers

My rings are standard vintage rings without pins or ramps but some short teeth (shift cages?). Anyway, if a chain retention device is still going to be required, I'm going to stick with 2x. If I need to have a front derailleur mounted, I might as well use it. I was hoping with a better chainline, bigger ring, and smaller range cassette I may have enough chain tension to keep everything on.


Thanks for the input.

ThermionicScott 

I have a Surly steel 49T/130BCD ring (full height teeth, no ramps or pins) if you're interested.

Shinkers

Thanks for the offer but I'm going to pass. I'm looking at chain guides at the moment, but will still likely just run my double.

ThermionicScott 

Rats, I'm never gonna get rid of this thing.

Jadesfire 

Not a 1x7, but a 1x8 with a 42t chain ring. No retention system, I did just need to spend a little time getting the RD adjusted exactly right. IIRC, the BB axle is 118mm...maybe 120.

Lascauxcaveman 

Similar to what I had to do. Chain length, spindle length, RD adjustment all had to be messed with as
I changed the bike around from 1x7 to 1x8 to 1x9.

jimmuller 

Not 1x7 but 2x8: My Tommasini has a Shimano 8-speed cassette. Chainline is problematic. In gears I tend to use a lot, rotating the crank backwards to pick up a toe clip after stopping can sometimes cause the chain to jump chain rings. The FD at least provides some control over the chain. Without the FD and the second ring I'd have to reach down and re-attach the chain manually.

63rickert

The short teeth are almost certainly the problem. A very badly worn chain or sprockets, bad chainline, bad frame alignment could cause similar problems. Perfect chain and perfect alignment are not necessary, but horrible won't work.

I rode CX with 1x7, no problem. MTB with 1x8 and 1x9, no problem. For those who remember early days of offroading doubles and triples caused nasty chainsuck, chain snarls, and the chain broke frequently. Using a single stopped all that and caused no new problems.

Vintage parts work. Their default program is to just work. Modern parts work perfectly. Until you attempt to use them one micron beyond their assigned role. They do exactly what they were created to do and will not do anything else.

Shinkers

Success! I swapped my ring for a nearly new vintage ring and decided to leave the FD on. I was able to set the FD in a position so it doesn't rub anywhere yet it should still keep me from derailing. A plus is that it's a lot more stylish than a standard chain guide.


I'm stoked.

tashi

Glad it's working for you, i've never had much luck on anything rougher than smooth pavement with regular rings. If you want to drop the derailleur and eliminate the possibility of dropping the chain a narrow-wide ring will work very well.

MarcoBianchi

Running 1x8, 38-11/28 on my commutter with really cheap parts, Alivio RD , the key is a 15$ single speed chainring, no retention mechanism is needed.