I’ve decided to go single ring on my CX bike, it’s Shimano 105 5700 drive train with a 36/46 up front and 11-28 out back.

I’ve gone for a 38t narrow wide superstar ring off the classifieds on here; so if I want to keep the same bottom end (the important bit to me) will a 30t cassette suffice or should I plump for a 32 one?

Is there any need for a front chain guide as I won’t have a clutch mech with it being shimano road.

38/30 or 32 both give a lower gear than 36/28

Is there any need for a front chain guide as I won’t have a clutch mech with it being shimano road

Probably

I’m running a 38 tooth Hope narrow wide on mine with no chain guide and a vanilla 105 rear mech. No trouble so far and it was very muddy at Penshurst today!

36:28=34.7″ gear
38:30=34.2″ gear

I’m also running narrow wide (SRAM Force) and the chain hasn’t budged from the front chain ring yet after four races so far. I have managed to rip apart my rear mech (105) and gear hanger already though. 😳

Similar radio’s when I started and went single ring last year.
Using 105 5700 as well and used a Narrow/wide 38 front ring with a 12-30 Ultegra cassette.
Just started using a XT 11-32 cassette and I think this gives a better spread of gears.
When using a Shimano rear mechanism with a narrow wide ring there is a mod to tension the spring on the cage.
It is on the Park website and was on the Absolute Black website.
Thanks,
Max

Steve, I’m running my 1×9 mtb with an on one single speed front ring (so not narrow wide but with deep unramped teeth) and with the rear mech spring mod I haven’t dropped a chain… That’s a rigid mtb in the peaks so buuuumppppyyy!

I’m going to run the same mech mod on my cx with the 40t nw I got to in place of the 38 with no front guide.

Spring mod:-

http://www.parktool.com/blog/repair-help/#article-section-3

I’m running 42 ring, 11-32 cassette (sram force 11 speed)… and I only recently struggled on a crazy-steep CX course, 99% of the time it’s perfect.

I think I’ll leave the 42 on there and get the 11-36 cassette. A 38 wouldn’t be enough high gearing on the flatter courses for me.

I think I’ll leave the 42 on there and get the 11-36 cassette. A 38 wouldn’t be enough high gearing on the flatter courses for me.

😯

I’m 1×11 with a 38T NW front and the standard rear (11/28 IIRC), just done a pan-flat course today, Strava/Garmin shows my top speed as 25mph and I don’t think I even troubled the bottom few cogs!

I’ve got SRAM Rival 1 on the Raleigh RX Race 2016 I’m reviewing at the moment. Not especially impressed. Lost the chain about 4 times in half an hour this weekend, the mud just got so thick it was pushing the chain off the teeth. So either a chainguide or regular bike changes is needed methinks.

Guess I’ll go for the 12-30 then