Specialised Sirrus X Chainring change
- Thread starter Orfeus67
- Start date
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Cycleops
Legendary Member
- Location
- Accra, Ghana
You need to post a pic with some dimensions. Specialized use an unbranded crankset so finding alternative rings might be difficult. If it's a square taper you might find 50t crankset out there somewhere something like this:
Amazon product ASIN B071769J15View: https://www.amazon.com/CYSKY-Single-Crankset-Crankarms-Bicycle/dp/B071769J15
You'll also need a longer chain.
to the forum.
Amazon product ASIN B071769J15View: https://www.amazon.com/CYSKY-Single-Crankset-Crankarms-Bicycle/dp/B071769J15
You'll also need a longer chain.
to the forum.
fossyant
Ride It Like You Stole It!
- Location
- South Manchester
You'll lose out on hill climbing. Is it just a single front ring
thanks for the replies so far.
So, the Sirrus X comes standard as one on the front (40T) and eight on the back (11-42).
If I fit a 50 on the front, looking at a Gear Calculator I reckon this will mean I lose the 42 on the back, with the 34 then becoming the lowest gear (currently second lowest gear). Given it is fairly flat round here and I rarely go lower than 3rd gear, this should be a reasonable pay-off to get a bit more speed.
Anything I can source in the UK to go on the front?
So, the Sirrus X comes standard as one on the front (40T) and eight on the back (11-42).
If I fit a 50 on the front, looking at a Gear Calculator I reckon this will mean I lose the 42 on the back, with the 34 then becoming the lowest gear (currently second lowest gear). Given it is fairly flat round here and I rarely go lower than 3rd gear, this should be a reasonable pay-off to get a bit more speed.
Anything I can source in the UK to go on the front?
Ajax Bay
Guru
- Location
- East Devon
https://www.specializedconceptstore.co.uk/product/17011/2020-sirrus-x-3-0/
How many bolts on the chainring and how far apart are adjacent holes (centre to centre in mm)?
Cassette 11-42t and has a BSA threaded 68mm bottom bracket
How many bolts on the chainring and how far apart are adjacent holes (centre to centre in mm)?
| CHAINRINGS | 40T, Narrow-wide Steel |
A 50t chainring won't necessarily give you more speed. It will just make you pedal more slowly. Presume your smallest sprocket is a 12t? It will only help if you are continuously riding on the 12t and running out of revs. But at this point on an 87" gear, you should be riding at 25mph plus, which is not bad.
If you do opt for a 50t ring, then as said above, a longer chain will be needed and possibly a new cassette as a new chain on an old cassette may not work together.
An alternative would be to consider a different cassette first, with an 11t and if you don't need the bigger sprockets, go for a more compact cassette with closer gaps.
Edit: miss read your earlier post. Notice you already have an 11t cassette. Bt a more compact cassette might help
If you do opt for a 50t ring, then as said above, a longer chain will be needed and possibly a new cassette as a new chain on an old cassette may not work together.
An alternative would be to consider a different cassette first, with an 11t and if you don't need the bigger sprockets, go for a more compact cassette with closer gaps.
Edit: miss read your earlier post. Notice you already have an 11t cassette. Bt a more compact cassette might help
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Cycleops
Legendary Member
- Location
- Accra, Ghana
Don't think that's a common size but the good news is that looks like a square taper BB so you can simply buy another chainset as I suggested above and swap it over.
The other thing you need to check is the clearance between the chainring and the frame chainstay. Will it take a much bigger chainring or will it foul?
If you're not sure post a pic from above.
The other thing you need to check is the clearance between the chainring and the frame chainstay. Will it take a much bigger chainring or will it foul?
If you're not sure post a pic from above.
This might help in determining your BCD, if you can't see it marked on the ring:-
Wolf Tooth - How to measure Bolt Circle Diameter (BCD) – Wolf Tooth Components
Wolf Tooth - How to measure Bolt Circle Diameter (BCD) – Wolf Tooth Components
Thanks everyone for your advice on this query. You might have guessed that I'm a newbie at bike upgrades. The downside of being in lockdown is that riding every day has made me more critical of my bike! (Well, not riding today, too cold/wet.)
Cycleops - do these photos resolve your question?
Cycleops - do these photos resolve your question?
Attachments
fossyant
Ride It Like You Stole It!
- Location
- South Manchester
That's a one piece chainset, he will have to replace the lot, not just the chain ring.
HarryTheDog
Guru
- Location
- Basildon Essex
Yes looks like @fossyant maybe/is right, those 4 bolts look like they just keep the chain guard on and the chain ring is part of the whole pedal crank assembly, however I think its square taper as @Cycleops says so sourcing a alternative maybe be easy.
such as https://www.tritoncycles.co.uk/comp...sunrace-single-ring-square-taper-crank-p19979
well maybe not that one as 96bcd, chainrings only seem to go to 40T.
such as https://www.tritoncycles.co.uk/comp...sunrace-single-ring-square-taper-crank-p19979
well maybe not that one as 96bcd, chainrings only seem to go to 40T.
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weareHKR
Senior Member
- Location
- North East Coast - UK
If you want budget gear.... some on fleabay! assuming it's a square taper for these!
Budget Cranks & chainring (Narrow WIde)
Budget Cranks & chainring (Narrow WIde)
Cycleops
Legendary Member
- Location
- Accra, Ghana
Yes, thanks. It looks like you have the clearance to fit a larger chainring but does look tight.
