Thinking of going 1x10

othello

I've got an CX bike as my winter/hack bike and I've done the occasional Wessex race on it, and I want to do a few more this season.

I quite fancy running 1x10, mainly because I like the simplicity of it, and also because my current set-up is a standard compact (50/34) which isn't ideal for cross. But I'm not sure what chainring size and rear cassette ratios to go for. I'm running 10spd Campag and don't want to change.

An added complication is I want to use the CX bike on the road during the winter. The lanes around me are full of gravel and holes and last winter I rode my CX bike on them, sometimes with cross tyres, sometimes winter road tyres. If I go too low with the gearing for cross I will be under geared (a lot) on the road.

Having read up, it seems some people go 44t up front and 12-30 on the back. Still seems a little high for cross and will be short cage Campag mech cope?

Or 38t up front and 12-27 rear and accept that I'll be spinning like crazy on the road?!

Any thoughts?

tgotb

The only real way to figure this out is to look at what gears you use (both racing and on the road) and make sure they're covered by your 1x10 setup.

By way of example, I've also just moved to 1x10. I was previously racing on 33/42 and 12-28 and getting a lot of use out of the lowest 33x28 gear. Using the smallest available single chainring for 110BCD, a 38, means I need a 32 sprocket to get a similar lowest ratio. Going with an easily-available 12-32, this gives me a top gear of ~85", which is the same as my track bike (ie plenty high enough). Quick check of the intermediate gears shows no horrible gaps; I've only ridden the new setup a couple of times, but very happy with it so far.

Note that I'm an inveterate spinner; these ratios may be totally wrong for you, but the process should be the same; the starting point is always to figure out which ratios you actually use...

devhads

I'm running a 1x11 set up and have been running a 42t front narrow wide chainring and 11-32 on the back. This has been a good enough range for road use and training off road/gravel paths. Yes, there are some gaps in the ratios but that's the compromise.

Seeing as it takes 5 minutes to change the chainring I've also got a 38t which I expect to use on the hillier courses for racing. I've also bought my son a 36t narrow wide chainring for his cross/road bike so could if needed go as low as 36x32

if you're planning on going 1x10 without a chain catcher you'll need to use the narrow wide rings and as you're on a compact you can't get them in 44t anyway. In the UK you can get 38t, 40t or 42t on 110bcd. I had to get my son's 36t from USA.

I set it up originally with an Ultegra medium cage but this was very flappy and had loads of chainslap so took a punt on a short cage fitting and it does. Went on a 50 mile off road ride last weekend with it and it was noticeably better with the short cage mech. Don't know about the Campag mechs though.

lesfirth

Campag max rear sprocket is 29T. I think that is for all cage sizes. I run a 29T with a Centaur short cage and it does not look as though it would handle anything bigger.

devhads

I don't know about the specifics of Campag but I should say that the Ultegra 6800 short cage I have, quoted a max sprocket size of 28t but it fits my 32t, only just with the B screw all the way in.

As you are going single chainring you don't have to worry about chainwrap capacity as this is only relevant when changing from the small to the big ring. What you need to consider is the actual parallelogram as this will determine the max sprocket size as opposed to the chainwrap capacity.

I looked at the tech docs for the long cage and the short cage and the parallelograms were exactly the same, so saw no reason why it wouldn't fit. My plan B was to swap the cages over if the parallelograms were different

othello

TGOTB wrote:

The only real way to figure this out is to look at what gears you use (both racing and on the road) and make sure they're covered by your 1x10 setup.

I'm sitting down with a pen and paper and Sheldon's gear calculator and working it out

reg_

Does this help

http://www.gear-calculator.com/#

mikpem

I've changed mine to 1x10 for this season and I've really enjoyed the practice runs on it but my first test in anger will be this weekend with a very sleep hill involved so if I can ride up that on it I'll be ok for the rest of the season.

I was also on a compact 50/34 last season with a 12-28 cassette, I found that I was doing every race on the 34t but it was spinning a bit too much on the straights. I've kept the same cassette and gone in the middle with a Race face narrow-wide 40t chainring and on the road commuting to work I manage a decent pace keeping up with traffic without going all crazy legs!

othello

mikpem wrote:

I was also on a compact 50/34 last season with a 12-28 cassette, I found that I was doing every race on the 34t but it was spinning a bit too much on the straights. I've kept the same cassette and gone in the middle with a Race face narrow-wide 40t chainring and on the road commuting to work I manage a decent pace keeping up with traffic without going all crazy legs!

I guess the worry is, will you have a low enough range?

Going from 34x28 to 40x28 bottom gear is a jump, but only one way to find out! Let me know how you get on.

devhads

my first test in anger will be this weekend with a very sleep hill involved

Basildon? I haven't raced there myself but I overheard someone say at training the other day it's rideable with a 34x32 but it would be quicker to run.

I'll have a 38x32 lowest gear.

mikpem

Yep, Basildon, I only got to watch last year because I was looking after the little one but said I was doing it this year no matter what, I only have the small matter of having to get back to Ipswich for my engagement party at 6.30!!

Most people seemed to be running last year but I really want to give it a go at riding up it. I should be ok, my technique is hugely lacking, my fitness left me about 8 years ago but my leg power is half decent and I just picked up some new knobbly tyres for the new season.

Will you be doing it this year then Devhads?

devhads

mikpem, yes I'll be going. I'll be there early for my son's race then a lot of hanging about for me to pootle around near the back of the vets.

Congrats on your engagement!

mikpem

Oh dear, that was a struggle....

Well I can declare that it is indeed possible to complete the Basildon course with a 40-28 lowest gear but I would possibly not recommend it, 6 laps in and my legs were screaming every time I got to one of the three hills (I ran/walked the last 2).

Luckily the rest of the season is a bit flatter from what I saw last year so I should be alright but that was pushing it a bit too far.

Based on my experience this weekend I would probably suggest going with a 38 chainring with a 12-32 if possible, that should give you a decent enough top gear with a bit more help to get up the hills.

I'm going to stick with mine for now, my next race is Chelmsford which is much flatter so I'll see how that goes.

I can also recommend the Receface narrow-wide chainrings, there were some high speed, very bumpy sections and everything stayed together as it should, if the chain was going to come off at all it definitely would have!

devhads

It was a bit of a beast wasn't it.

I did a couple of practice laps on a 38x32 then changed to a 36t front chainring. I didn't find I ran out of high gears as the downhill sections were all fairly technical and to be honest I was happy to spin or even freewheel after the hills. I enjoyed it though, didn't trouble the scorers but won my own little battles.

othello

I've got my new cross bike built up and as an experiment I'm running a 38t front with a 12x29 rear. I've put on an old Deore chainset I had in the spares bin, which means I can use a 104BCD narrow/wide chainring (these are much cheaper). Seems a pretty good range so far. I'll report back!

mikpem

You should be fine with that, this week I had a much better race on the 40:12-28 but then it was a much more sensible course. By the looks of things your set up should be just about perfect.

That's an interesting thing about 104BCD being cheaper, I'm building up a Planet-x Uncle John as cheaply as possible for the mrs at the moment and am yet to get the gearing sorted, I might take a look at a Deore crank as an option. What make of narrow-wide chainring are you using?

othello

mikpem wrote:

You should be fine with that, this week I had a much better race on the 40:12-28 but then it was a much more sensible course. By the looks of things your set up should be just about perfect.

That's an interesting thing about 104BCD being cheaper, I'm building up a Planet-x Uncle John as cheaply as possible for the mrs at the moment and am yet to get the gearing sorted, I might take a look at a Deore crank as an option. What make of narrow-wide chainring are you using?

I picked up a narrow/wide from Superstar Components as they do a 38t 104BCD. It was approx £25 (free delivery) and looks pretty good quality. They do a full range of different rings too, and in snazzy colours