Chainring or Cassette Change

[Jako De Wet]

Hi there

 

This is very similair to https://community.bikehub.co.za/topic/180520-chainring-upgrade/ but didn't want to jump on that thread.

 

I ride a lot of steep climbs and doing 1800m+ ascend in a race is not uncommon. I currently have a 32T with a 11 speed 11-46.

 

I have been toying with the idea of getting a 30T that I can swop out on the days where I know I will be doing lots of climbing. The other alternative is going for the Sunrace MX8 11-50 cassette, but looking at the gear ratios, it seems the cheaper option would be to just swop out for a 30T on certain days?

 

32T 11-46 : Max ratio 3.23 : Min ratio 0.77

30T 11-46 : Max ratio 3.03 : Min ratio 0.72

32T 11-50 : Max ratio 3.23 : Min ratio 0.71

 

So when I look at this it makes sense to maybe get a 30T as I won't need that much top speed when doing a climb orientated event? Or am I completely missing the plot?

 

http://gears.mtbcrosscountry.com/#29/2.30I1567I10656

[splat]

How much top speed you need is up to you.

 

I think the best combo of gears (for me) would be a 34T ring up front with a 10 or 11-50 cassette.

[Jako De Wet]

I have a Shimano SLX, Shadow Plus GS derailleur, will it be compatible with a 11-50 cassette?

[cpelser]

It will work, but maybe at a bit of a stretch. It depends on whether you have the short/medium or long cage derailleur. What crankset do you have? I think swapping out the chainring is the easiest option. Especially if you have a direct mount chainring as found on sram cranks and Rapide and Lyne.

[Jako De Wet]

I have a SRAM NX crack with direct mount. Frame is boost 148mm as well, so a 3mm chainring also seemed like the first option, if it doesn't work, its a cheaper mistake to make.

[cpelser]

Yes, and don't be phased with which chainring you get, just get a Rapide cheapie.

PS also read up a bit on oval rings

[Tomik]

Putting a 30T on that setup will suit you fine. I run a 30 with a 10-42 and have no problem with any climbs in/around Cape Town. Raced the Tiletoria 70km up Groenlandberg and it was perfect. 

 

No issue with top end either unless I'm on the road (chance to enjoy the views). If the race has more gravel, swop to a 32/34. With a 46 at the back, a 34 should be OK. If not, train more. 

[Jako De Wet]

I was looking at Rapide, but they don't have a 30T

[DieselnDust]

You r SLX derailleur is going to be severely challenged to work reliably with a 50T cassette. I'd suggest you get a Wolftooth goat link to lower the derailleur a little and thus create some additional capacity for it.

 

https://www.evobikes.co.za/wolftooth/wolftooth-goatlink-11-speed.html