rear cassette choice

[andrewsdad]

^^^ I have 8 speed and went from 11-32 to 11-28...Tredz sell it in that size...next time round though, I might try a 12-23...the difference is noticeable and I barely use my low gears, so I'm after crispness...here's some links to Shimano's offering...wiggle and chainreaction sell the same cassette for cheaper, but the size range isn't the same...wiggle will probably get you the speediest delivery time...if that effects your choice...

http://www.tredz.co.uk/.Shimano-CS-HG50-8-Speed-Road-Cassette_33610.htm

http://www.wiggle.co.uk/shimano-hg50-8-speed-cassette-road/

http://www.chainreactioncycles.com/shimano-sora-hg50-8-speed-road-cassette/rp-prod1864

Thanks for the links, very helpful , the 11/28 sounds ideal i'll try that.

 

[andrewsdad]

The high gear won't feel much different but the low gear will be far more noticeable. Bear in mind that with an 8 speed cassette and such high and low gears, there will be a big step from one gear to another. It may feel like you are never in quite the right gear.

Thanks for your reply

 

[andrewsdad]

It really depends on the type of roads you ride on. If you have lots of really steep climbs (and I'm talking about15+%) then you may find some value in the 11-34 over the 10-30. It would give you a gear that should be able to get up just about anything (although you don't say what the front gearing is, I assume it is something quite forgiving)
If you don't live in real mountain goat territory I would stick with the 10-30 as the steps between each gear will be smaller and thus feel more comfortable when you are changing gear

I commute the majority of my ride is uphill returning home, im not hitting too fast downhill as I don't have the extra gears, so maybe the 10 rather than the 11 would be better, thankyou for your reply.

I am old and fat and ride 50/38 at the front and 13/26 cassette at the rear. On my regular routes around here, I can do all the climbs, such as they are, in no lower than fourth gear. On of my other bikes has 39/53 with a 12-23 cassette both on 9 gears. I tend not to need first but find I spend more time on the small chain ring.

I have naturally quite a fast cadence and I would find the big jumps between gears a pain. I live in the flatlands though. A ride of 25 miles with more than 500m of climbing is hard to find. If it was hilly I suppose it would be nice to know I had a dinner plate option.

You don't say what sort of bike you have. Make sure the rear mech has the capacity to take the change.

I got the bike built from a reputable shop, it's a reg road bike. though had a few run ins as the owner refused to honour the warrenty, hence why im doing this myself, thanks for your help

 

[Nigelnaturist]

@andrewsdad try and stay away from the HG31/41 quality isn't as good as the HG51 I have never had a 31 but the 41 did suffer from rusting, never had the same problems with the 51.

 

[SatNavSaysStraightOn]

One thing to bear in mind will be the rear derailleur. If you are on something like an 11-25 you may be able to take it to an 11-28 without issue, but an 11-30 may be beyond the reach of the rear derailleur if it is a short cage RD. I had this issue with my Triban 3 when I first got it. I could just squeeze a 11-28 onto it. The actual spec of the derailleur was for a 26T max range, but there was just enough leaway in Shimano's design to get away with an 11-28. It won't be a problem if the bike already has an 11-30 though, because it will have a longer reach RD on it. But I thought I would mention it.

 

[SatNavSaysStraightOn]

I commute the majority of my ride is uphill returning home, im not hitting too fast downhill as I don't have the extra gears, so maybe the 10 rather than the 11 would be better, thankyou for your reply.

If you are not going too fast, you may want to look at what is on the front, as well as what is on the rear.

 

[andrewsdad]

10/30? Not sure that exists.

Sorry i thought id seen it on ebay, shows how much of a novice i am.

I can't find the 10-30 8 speed cassette anywhere online.

Comparing the 11-30 and 11-34, the only difference in cogs is the largest one. The rest of the cassette has the same exact ratios.

I was mistaken i thought id seen this on ebay thats the novice in me lol

 

[andrewsdad]

One thing to bear in mind will be the rear derailleur. If you are on something like an 11-25 you may be able to take it to an 11-28 without issue, but an 11-30 may be beyond the reach of the rear derailleur if it is a short cage RD. I had this issue with my Triban 3 when I first got it. I could just squeeze a 11-28 onto it. The actual spec of the derailleur was for a 26T max range, but there was just enough leaway in Shimano's design to get away with an 11-28. It won't be a problem if the bike already has an 11-30 though, because it will have a longer reach RD on it. But I thought I would mention it.

Im really not sure, its a claris so maybe to save any hassle ill replace like for like. Thankyou

 

[Nigelnaturist]

Depending on the front ring even a 50x11 @120" on an aveage road bike you will hit the mid to high 30's before spinning out, I generally spin between 90-100 rpm at 95rom the 50x11 would be 35mph. I spin out about 105-110 mark and that would be 40mph, this is why I start at 12 as I don't spin that on the flat.

 

[andrewsdad]

@ayceejay it is that simple I have been doing since I started cycling.
@S.Giles close grouped cassettes are usually used to keep cadence in a certain range, which is why most start at 12th as it will have closer ratios e.g. HG50 8sp 12-13-14-15-17-19-21-23, the only two missing over my 10sp are the 16 and 18th cogs, and having used them on my current set up, the addition of that 18th is brilliant. I had a 105 12-27 (12-13-14-15-16-17-19-21-24-27), the only other option on a 105 was the 12-25 only the lower gears were different at 23-25 the rest being the same, so I had to get a Ultegra 12-23, I have since found out I can split a Tiagra cassette, I can't split the low three gears on 105/Ultegra as they are on a spider, so I could take the low three gears from the Tiagra 12-30 and use the 19-21-24, the 24 being the one thats different as this would give that little extra, and the jump from 21-24 whilst not brilliant isn't very bad either, but i really noticed the gap between 17-19, this why i have gone down the route i have and stuck with the triple as I have so many options, I constantly hear about people with compacts wanting a lower gear ect.... but not very often how to get closer grouped ratios, maybe I am doing something wrong in my cycling.

Thankyou you for your reply

 

[Turbo Rider]

Im really not sure, its a claris so maybe to save any hassle ill replace like for like. Thankyou

You have range of 32 13 to 25 11 for Claris...it's a broad range...and hg50 is the perfect fit for the brand

http://cycle.shimano-eu.com/publish.../product.-code-RD-2400-SS.-type-.rd_road.html

 

[Nigelnaturist]

Im really not sure, its a claris so maybe to save any hassle ill replace like for like. Thankyou

Almost any modern road RD in a GS (medium cage) will do up to 32th, if you subtract the max number of teeth and minimum number on both cassette and chainset then add them this is the capacity the RD needs to cope with i.e. mine 50/28/28 is 22th my rear is 12-23=11 capacity is 33th, change the rear to a 11-28 and its 37th, the rear being 17th difference, also 9 and 10sp RD will work with 8sp so you can fit better quality components.

 

[bpsmith]

Sorry i thought id seen it on ebay, shows how much of a novice i am.

I was mistaken i thought id seen this on ebay thats the novice in me lol

No apology required fella!

 

[andrewsdad]

If the OP is very unfit and in a very hilly area then the 34 could be a decent bail out gear. Otherwise I'd go for the 30. Even if very unfit I wouldn't recommend a 34 unless the hills are 20%+. Use a 30 and after a couple of months it'll feel like plenty of gear

Im reasonably fit though 30 milers is about my limit. Thanks for the advice.

 

[andrewsdad]

@andrewsdad try and stay away from the HG31/41 quality isn't as good as the HG51 I have never had a 31 but the 41 did suffer from rusting, never had the same problems with the 51.

Great advice many thanks.