MTB cassette on Road Bike?

[KennyWilson88]

Hi Guys

I currently have a Sora chainset on my Road Bike and am looking at doing some upgrades on it ready for the manchester to blackpool cycle.

I was thinking of replacing my 8 speed 52t chainring to a 50t and also chainging my cassette from 12-23 over to 11-34 however it is a MTB cassette.

What are your thoughts on this? Will it work? what would you advise?

Thanks

 

[clid61]

Yes it will work however, you will need a longer rear derailleur and longer chain too.

 

[lpretro1]

It may or it may not

 

[HarryTheDog]

If your rear mech is also a sora the 3300 sora 8 speed biggest sprocket is 27T, the newer 3500 9 speed is a max of 32. So you might have a problem wth it. Are the shifters and mech sora? just because the crankset is sora the mech may not be.
http://cycle.shimano-eu.com/publish.../product.-code-RD-3500-GS.-type-.rd_road.html
http://www.shimano.com/media/techdo...RD-3300/SI_5TT0C_EN_v1_m56577569830606897.PDF

 

[KennyWilson88]

Hello

Thanks for your replies, The Mechs are Sora seems i might have a compatibility issue doing this.

What would you recommend that i do to change all of this?

 

[Nigelnaturist]

@HarryTheDog I wont make any difference whether the shifters are sora or not, so long as 8sp compatible.
@KennyWilson88 if you want to fit a 34 th large rear, you will need to fit a MTB RD, Acera or Alivo are cheap enough £15-25, what is your inner ring, you didn't say if its a triple or not, if it is, if its a 74BCD inner you can fit a smaller ring, say a 28, providing there isn't more than about 12th between rings, I have a 28/38/50, but have had it set up with a 26 inner, this couple with the 12-27 I had gave a range of about 26-110"
Same applies if it is a double though options are much less. Without knowing your inner rings I can't advise more than this, but by changing the front you could fit say a 12-27 (not sure what 8sp cassette range is at the mo need to check) and keep both the FD and RD as is (with any necessary adjustments)

 

[KennyWilson88]

Hi

Thanks for your reply It is a double 52 - 39

 

[Nigelnaturist]

@KennyWilson88 ok you can certainly fit a 38th inner ring which will help, if its a square typer cranks can be got for £20 so it would be possibly to convert the front to a compact setup for about £50-55, unless it is already a compact crank set, though it unusual to have a 39-52 on compact from new. What makes a compact crank is the Bolt centre diameter (its how the holes are measured) a normal is usually something like 130mm BCD a compact is 110mm, you get this figure by measuring the distance front the centre of one bolt hole to the next, then use a table to look it up. Normal doubles and triples (you can get compact triples) are usually 130mm BCD inner/outer or 74mm inner and 130mm middle/outer triples, this doesn't answer your problem.
I take it this is your current set up, ignore the colours, top figures are the front chainring sizes in teeth, the left the rear cassette, the mainly green is gear inches.

a 52/38 and a 12-26 gives this

a 39/50 and a 11-32 this

You can see why the 11th is almost redundant and there are some pretty big gaps.

this is a 50/24 12-25 setup

If you go for the MTB cassette you will need a new RD cassette and chain, everything else will work, though will need adjustment, I know because I have done it with sora kit,

 

[Hacienda71]

Manchester to Blackpool is pretty flat. I would just stick on the max tooth cassette Sora will take probably 28t. You will need a new chain as well.

 

[400bhp]

Pointless. Stop fretting and just ride your bike.

 

[Nigelnaturist]

Pointless. Stop fretting and just ride your bike.

However some people like to tinker to, and it also helps you know what is right for you, I know from choice I will never ride a 50/34 setup, its just to big a change, almost all my riding is done on the 50/38 front and 12-23 rear, but a low 28inner up front if needed, and that makes it higher geared than many a 50/34 set ups when people look for lower gears, I found this combination works for me through trial and error. However I was faster on a 52/40/30 and a 12-27.

 

[400bhp]

However some people like to tinker to, and it also helps you know what is right for you, I know from choice I will never ride a 50/34 setup, its just to big a change, almost all my riding is done on the 50/38 front and 12-23 rear, but a low 28inner up front if needed, and that makes it higher geared than many a 50/34 set ups when people look for lower gears, I found this combination works for me through trial and error. However I was faster on a 52/40/30 and a 12-27.

Oh yes agreed. But the OP's post suggest a relative novice and (we're not even sure why the OP wants different kit) therefore there's no clear gain from either setup.

Now, if it was an 80 miler around the peak district, going up winnats pass etc, then I can see the logic.

 

[Nigelnaturist]

@400bhp I was doing it from the off, changing gear ratios making up my own, some worked some didn't, its how I found out a 15-18 gap is a big no-no for me, mind you I hate the 17-19 one two, its why I ende up with a 10sp 12-23 would just love that 11sp 12-25 on a triple front.