I’m looking at getting a different cassette for my gravel bike to give me a easier time going up steep hills. I’ll need a longer chain, no doubt; can I just take a few links from a random chain and slap 'em on, or should I start with a new chain
You can, but in my opinion, just get a new bike chain. They don’t cost too much. Especially if you are changing and renewing part of your gear system anyway.
Every extension and every rivet creates a weak link that could possibly break. You will end up regretting it in the long run.
It would depend how old your chain is, and also how perfectly suited to the current cassette it is.
So, if it was a fairly new chain and had a bit of room (ie largest cog front and read and still plenty of give in the derailer), then I wouldn’t change it.
If the chain was getting on then replace it anyway.
If the chain is pretty new, then adding in links will work, but as @P.Weikamp said - it does create a point of weakness. Then again, I’ve never snapped a chain (yes sub 1kw NM) so wouldn’t be worried, but if you are stronger / bigger than me, then I would suggest a new one.
So many variables.
While you’re at it, swap your shifter cables, lube the springs in the shifters, and enjoy the bliss of a new drivetrain / gear system.
You can add links to an existing chain. You may just end up with a chain that slips or bounces slightly.
This can be very annoying but on a gravel bike I reckon it won’t happen during a knarly descent .
So my suggestion: add links to the existing chain and try it. Just make sure that the links are more or less the same age / wear than the chain.
Decided to go with a whole new chain. I haven’t used sram before so I went with an 1170 chain to go with the 1170 cassette. Can’t wait to try it out!
this is with the original chain on big-big with the new cassette. Shouldn’t need installing the new chain. Evidently the 105 medium cage, though only spec’d to 34 tooth cassette, will go up to 40. I’m at 36, which is just 2 bigger then OE, but still give me a little extra spin when I have gear on board. Should be good enough for now.
I think that chain is a bit too short, maybe 2 links. A rear mech normally sits at a 90 deg angle on the biggest cog, but then again, I’m not a certified mechanic so I can be wrong
Main thing to make sure is that there’s still some spring in the cage at that extension. If it’s right near the limit you run the risk of knackering it.
You won’t necessarily need to lengthen the chain. It depends how much slack is on the current one. I’d test the current one before buying a new one unless it’s due for replacement anyway.
I built my current bike but previously I’ve been able to change cassette size without a new chain just by using up slack.
Edited to add: just seen the photo. It looks a bit tight, but I never use the big big combination anyway so if it works I’d go with it. What you don’t want is it breaking if you briefly cross chain by accident. If you are in the habit of using big-big then I’d want a bit longer.
well… i have a new chain, might as well use it. It’s only longer by one full link, but that’s about all the cassette size is bigger. and if it helps prevent breakdown out on the road, that’s a huge bonus
Hi Calvin, out of curiosity - what gears you running up front? 53/39, 53/36 etc? There are ‘compact’ chain rings out there, e.g. 50/34 or similar.
48/32. Its still not as spinny as a 3rd chainring.
I found this article informative https://www.google.com/amp/s/road.cc/content/feature/how-get-ultra-low-gearing-gravel-bike-adventures-246424%3Famp
Interesting read. I’ve read that the 105 can handle 40 tooth sprocket, i just wasnt that adventurous. May try it next season. As it is, it nicely handled an overnighter with minimal supplies - 80k, 1400m with a few double digit climbs. If i were to add tent and bedding etc I’ll probably want more gears.