tiagra cassette
- Thread starter Nebulous
- Start date
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RecordAceFromNew
Swinging Member
- Location
- West London
Firstly is your Tiagra rear mech a short (SS) or medium (GS) cage model? See this if you aren't sure. Secondly what is the tooth difference between the largest and smallest chain ring?
With a larger cassette you might need a longer chain. You can check what number of links you need compared to what you have with this calculator.
If you have a medium cage rear mech you might be able to squeeze a 11-32T cassette in to give you an even lower gear if you want, if the distance between the upper jocket pulley and the 25T cog is no less than 15mm.
With a larger cassette you might need a longer chain. You can check what number of links you need compared to what you have with this calculator.
If you have a medium cage rear mech you might be able to squeeze a 11-32T cassette in to give you an even lower gear if you want, if the distance between the upper jocket pulley and the 25T cog is no less than 15mm.
Thanks guys - I think its a mid length cage - I'll give it a go.
I'd be a bit sad if the chain isn't long enough, as I've just put on a new one - however if push comes to shove I'll get another new one, cut it a bit longer and swop them when I change cassettes. I don't expect this new cassette to be used very often, which is why I want to do it on a budget.
I'd be a bit sad if the chain isn't long enough, as I've just put on a new one - however if push comes to shove I'll get another new one, cut it a bit longer and swop them when I change cassettes. I don't expect this new cassette to be used very often, which is why I want to do it on a budget.
Okay - I've installed the hg 61 - it was quite straightforward. I didn't even have to index the gears.
However - the jockey wheel now looks scarily close to the biggest cog. The mech also seems very close to the spokes. It might be it always has been, and I just haven't noticed before. By the time I changed it it was getting quite dark, so I haven't roadtested it yet.
However - the jockey wheel now looks scarily close to the biggest cog. The mech also seems very close to the spokes. It might be it always has been, and I just haven't noticed before. By the time I changed it it was getting quite dark, so I haven't roadtested it yet.
2Loose
Guru
- Location
- Loughborough, Leicestershire.
B-Screw adjustment on the mech itself should move the jockey wheel a bit further away IF there is room in the chain to do so.
RecordAceFromNew
Swinging Member
- Location
- West London
AFAIK Shimano road rear mechs of the same model/series have exactly the same large cog capacity (because they have identical parallelograms) be it a SS or GS (which have different cage lengths, which determine chain wrap capacity), so most probably your Tiagra GS won't help you if a Tiagra SS is no good. Mtb rear mechs however generally have longer paralleograms, which will allow for larger largest rear sprocket.
Though I think it is unusual, although not impossible, for a Shimano road mech, which officially has 27 tooth max rear sprocket capacity, to not work ok with a 28T cog with careful B screw adjustment. But of course that is influenced by, amongst other things, rear dropout and gear hanger geometry.
As I kind of indicated in my earlier post above, the best way to spot the existing large rear sprocket capacity is to examine the clearance between the upper jockey and the largest cog, after allowing for a bit of room for the chain, every 2mm will allow an additional tooth.
Thanks guys - I had screwed in the b screw, but only a few turns. It still has room to go further. I'm impressed with that article, get a longer screw or put it in the wrong way round.
I've been happy with my 12-25 but I pushed to hard and died on a hill recently.
I've entered the Bealach Mor in a week's time and it's reputation, on top of my recent fail, was the motivation to change. If I don't like the bigger gap between gears I may well change back after I've done this event.
I've been happy with my 12-25 but I pushed to hard and died on a hill recently.
I've entered the Bealach Mor in a week's time and it's reputation, on top of my recent fail, was the motivation to change. If I don't like the bigger gap between gears I may well change back after I've done this event.
Had it out today - did 37 miles - all is well.
it's strange though, I didn't think I was very well tuned into my bike, but the bigger jump between gears certainly threw me a bit. I was also aware that I must be quite consistent with the gears I use in certain places - small climbs etc, because I kept thinking there was something wrong by the effort it was taking, but of course the gearing is different. I didn't climb anything noteworthy, but 34 - 28 feels very low, quite a difference from 34-25.
it's strange though, I didn't think I was very well tuned into my bike, but the bigger jump between gears certainly threw me a bit. I was also aware that I must be quite consistent with the gears I use in certain places - small climbs etc, because I kept thinking there was something wrong by the effort it was taking, but of course the gearing is different. I didn't climb anything noteworthy, but 34 - 28 feels very low, quite a difference from 34-25.
