Cycling UK Forum

My current set up is a road triple 50/39/30. I used this for the Pyrenees last year, fully loaded and although I just managed there was the odd occasion when I looked down and saw nothing was left and perhaps wished there was! Cassette is 11-32.

Any Issues with swapping the 30 ring to a 26 before my next tour (Pyrenees and French Alps). My chainset is a Shimano Tiagra 4503 triple. I was thinking of dropping in something like this from Spa for the tour just for them steep mountain passes.

http://www.spacycles.co.uk/products.php ... b0s149p245

Will this give me that little extra before I have to get off and walk and will it involve much tweaking?

I've just checked the BCD for the inner ring and it's 74mm so yes the 26t ring in the link will fit.
It should work with the exsisting set up without any tweeking.

reohn2 wrote:I've just checked the BCD for the inner ring and it's 74mm so yes the 26t ring in the link will fit.
It should work with the exsisting set up without any tweeking.

many thanks

Did you find your 50 useful? Might I suggest you go the whole hog and maybe try something like 42/34/26, assuming you can get your front mech low enough down the seat tube.

Just did a similar exercise with Ultegra 6603. Worked a treat

viewtopic.php?f=5&t=63075

I've been using 48/38/24 for years. 24 is the smallest that will fit on 74 BCD.
About the only thing that may happen is the chain dragging across the bottom end of the front mech if you use 26x11 or 26x13. Just don't use those gears (which you shouldn't anyway).

Have same Tiagra 4503 triple setup as OP. It was simple job, just removed chainset and bolted on the Stronglight 5 Arm 74mm Road Chainring 26T and refitted chainset, no tweaking gears etc. required.

Valbrona wrote:Did you find your 50 useful? Might I suggest you go the whole hog and maybe try something like 42/34/26, assuming you can get your front mech low enough down the seat tube.

The OP would need to change the chainset as it's a 130BCD for the two outer rings,whough it would take 48/38
Or for about the same cost as the outer rings he could buy one of Spa's own touring c/sets (48/38/28)and a s/taper UN54 BB for approx £45 plus £7 for a 26t inner,if he so wanted.

Valbrona wrote:Did you find your 50 useful? Might I suggest you go the whole hog and maybe try something like 42/34/26, assuming you can get your front mech low enough down the seat tube.

Given road mechs and indexed changers such ratios are difficult.

However back to the original question going to 26T will be fine. I had 48/38/22 for a while but found the jump too big. So I've gone to 48/38/24. Both of which are way outside the spec of the changers etc but work fine (sora front mech and shifter) but can be a bit lumpy back-pedaling on the lowest gear as the jockey wheel bumps along the sprocket (but under pressure it's fine).

50/11 seems a pointless top gear.

I have a 53/12 which I only use for long downhills and with-the-wind on the flat. 50/11 would never be needed - even by me.

For the OP, I'd be temped to change the cassette as well as the inner ring. 11t cog is too small IMHO.

Changing to a 26 inner ring might cause chain unshipping.
Buy a 'Dog fang' too.


I'll get my coat.


PS I have a 36 / 12 top on my sports tourer/Audax. 81". Plenty high enough. Removed big ring completely.

Low is 22 / 27 ( and needed a Dog fang !! )

Mick F wrote:50/11 seems a pointless top gear.

I have a 53/12 which I only use for long downhills and with-the-wind on the flat. 50/11 would never be needed - even by me.

For the OP, I'd be temped to change the cassette as well as the inner ring. 11t cog is too small IMHO.

I have a 46x13 top on the heavy rough stuff Kona Dew Drop, and a 48x14 on the ligher Thorn Audax Mk3.I rarely use top on either bike.
In fact I'm more likely to be in something like 46x23(Kona)or 48x23(Thorn) when descending fast,ie 40mph plus,as it keeps the chain tighter so it doesn't keep slapping the chainstay when I hit some rough road etc.

I changed a 30T for a 26T to give 52/42/26.

Potential issues for me were...

1. Chain unshipping due to the big drop. Meant to fit a device to prevent this but instead have mastered the knack of lowering it gently, even with STIs.

2. Big drop means 1 left shift > 3 right shifts, so maintaining cadence is impossible. This encourages me to use the inner only when really needed and not to wimp out, and I like that.

3. 26T inner only works with the inner four rear sprockets without rub. (21, 24, 28, 32) Again, not an issue. I just use 42:32 until it gets really steep and long

.

50/11 seems a pointless top gear.

I have a 53/12 which I only use for long downhills and with-the-wind on the flat. 50/11 would never be needed - even by me.

For the OP, I'd be temped to change the cassette as well as the inner ring. 11t cog is too small IMHO.

I use the 50/11 sometimes on the flat. Came in useful on a club ride when I had to stop but the others did not hear and carried on at a 20+ mph average. I had to use that gear over several miles to catch them all up. That was hard work. So most of the time it is useless but sometimes it is handy but I do ride in the flatlands alot.

I disagree with the pair of you.

I could never pull that gear on the flat, I would be faster in a lower gear.

However I do sometimes use my 52:11 gear when I am chasing the elusive 50mph on serious downhills, I havent made 50mph yet but over 40mph is the sort of speeds that you need this gear for.