[cycle zombie]

Hiya, I am thinking of converting my endurance bike to a single chainring set up. Opinions really however would a 1 x chainring with a 11-36 range cause issues. Surface will always be tarmac. Where I am based the terrain is mainly flat with generally only short inclines. Thanks.

Topic

[Welsh boy]

Crank length DOES NOT affect

Crank length DOES NOT affect gear size, the ratio between the chainring and sprocket and the rear wheel size are the only things which affect gear size so if you see a gear size calculator inputting crank length then you know that it has been done by someone who doesn’t know what they are doing. Similarly, if someone recommends a calculator which factors crank length into the equation they don’t know what they are talking about and you really shouldn’t take their advice seriously 

[Argos74]

I did a 1x conversion on a

I did a 1x conversion on a Shimano 105 crankset, works okay with a 42t narrow wide chainring. Will need a rear mech compatible with the cassette, I’m doing fine up moderately steep inclines with 11-36 at the back.

The other bike is 48t / 11-42, a decision I regret on a regular basis. 42t up front is plenty for 1x.

[kil0ran]

Assuming you’re running
Assuming you’re running Shimano bear in mind they make the 1x specific FC-RX810-1 chainset which might help with chain retention. It’s 11sp and Ultegra-level in the lineup. 46T or 44T options

[mark1a]

Whether you need a long or

Whether you need a long or short cage derailleur is down to capacity, for example on a 2x setup of 11-32 & 52-36, subtract the low from high in each and add them, you get 32-11=21 and 52-36=16, the sum is 37. RD-8000GS is 39 so that works. With your 1x of 11-36, so subtract 11 from 36, it’s 25, so a short cage will work, you’d just need to size the chain correctly. 

[cycle zombie]

Really appreciate everyone’s

Really appreciate everyone’s comments and ideas. I had thought of a single 46 but I hadn’t thought of being able to keep my rear mech as short cage. I probably need to have a further think about going from a double to a single based on some of the comments made. 

[Hirsute]

Personally I’d stick with the
Personally I’d stick with the 2x set up as you will find you end up between gears.
I’ve got an ebike with 46 and 11-42. To some extent I can vary the motor but still end up too low or too high.

[huntswheelers]

Use this my friend….   

Use this my friend….    http://www.gear-calculator.com   

Input the current 2x set up inc tyre size….

then press compare and input the 1x set up and find the one as close to what you are trying to achieve, as previous have said regarding chainring type but have a play and see where you want to be.

I use this calculator with my bikepacking customers to work out the best set up for them….. ride safe and good luck

[Simon E]

Unless you’re do a lot of

Unless you do a lot of chaingang rides a 46T chainring would probably be big enough – 46×11 is still a pretty big gear (110″) and it allows a lower bottom gear for when you need it.

Also you could consider using a 11-32 (38″ bottom gear) so the steps between ratios are smaller, then swap to a 11-36 (33″) if you want to ride somewhere hillier.

[wycombewheeler]

any inaccuracy on rolling

any inaccuracy on rolling diameter will apply to before and after equally, so really it’s just a question of ratios, and 39/28 appears to come out equal to 52/36 (less than 0.5% difference)

[wycombewheeler]

Dnnnnnn wrote:

You’d need a ‘narrow-wide’ chainring to hang onto the chain better in the absence of the front derailleur cage. And a long cage rear mech to take up the slack chain when you’re not in the bigger sprockets (which you’re unlikely to use much if it’s a mostly flat area).

If OP uses an 11-36 cassette and a single chainring they are unlikey to need a long cage rear mech.

A short cage rear mech is adequate for a 39/52 and 11-28 set up, this equates to the derailleur accomdating a difference in chain length of ((52-39)+(28-11))/2 = 15 links. OP is only looking for (36-11)/2=12.5 links, should be no problem for his existing derailleur.

[wycombewheeler]

seems like a limited range,

seems like a limited range, what size chainring are you thinking of using?

46 teeth (for exampe) would deliver a 10% reduction in top speed when spinning out (compared to a 50/34 chainset), meanwhile, the 46×36 gear, would be equivalent to 26.6 teeth on the largest sprocket.

So if you currently get away with an 11×25 cassette with your 34/40 chainset, then you will be ok on the climbing. 

But of course while you usually ride on the flat, you will be comitting to never heading to the big hills with such a set up.

Also you might notice the gaps between the gears if you go from 11/25 to 11/36

[HoarseMann]

Sriracha wrote:

Sriracha wrote:

HoarseMann wrote:

I can’t vouch for the accuracy of this site… seems to indicate…

It’s not some voodoo shit, surely? It’s front teeth divided by rear teeth times rolling diameter. Where’s the latitude for inaccuracy?

I couldn’t be arsed to do the math just before before bed?!

[Critman]

Sheldon Brown’s Bicycle Gear

Sheldon Brown’s Bicycle Gear Calculator provides a gear chart with gain ratios. Input tire size, crank length, chain ring size/s, and cassette sprockets. I use it to see ratios using different size chain rings.

https://www.sheldonbrown.com/gear-calc.html

[Sriracha]

HoarseMann wrote:

HoarseMann wrote:

I can’t vouch for the accuracy of this site… seems to indicate…

It’s not some voodoo shit, surely? It’s front teeth divided by rear teeth times rolling diameter. Where’s the latitude for inaccuracy?

[HoarseMann]

I’d look at putting some

I’d look at putting some numbers into a gear calculator – I can’t vouch for the accuracy of this site: https://www.bikecalc.com/gear_inches but it seems to indicate that the lowest gear on the setups you quote is the same at 37.10 inches. So the only downside to 1x would be bigger jumps between ratios and spinning out slightly sooner downhill.

[Author]

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