europa

After some on bike thinking and a play with Sheldon's Gear calculator (thanks Sheldon), I've decided that I can improve the riding of my 2007 model Trek520 by changing the 30 tooth chainring for a 26 - lots of decent hills here, big heavy me noticing the decent hills, the change would lead to a definite improvement in how the bike works for me (an extra gear and a sensible shifting pattern from middle to small chainring). The 42 tooth middle ring is perfect for my use so I'm not touching that.

The bike is the current model - Ultegra cranks. She's done about 800km so the shop isn't going to consider a 'free upgrade' on the parts and I'm not going to fork out money for a different set of cranks - it's not that big an issue. If I can just change the 30 tooth for a 26, I'll be happier than I am now (which is pretty darned happy).

BUT, my lbs rang their supplier and Shimano don't make a 26 tooth chainring for the Ultegra crank.

Is there an alternative? Or am I just going to have to get stronger?

Richard

operator

I know the mountain bike group (deore) has 26t chainrings but I can't comment on compatibility.

europa

Don't think it is mate - the blokes who change the gearing on the 520 usually talk about changing the cranks as a unit to deore. I don't mind discovering I'm wrong though.

Richard

HillRider

Anybody's 26T 74 mm BCD chainring will fit just fine. Harris Cyclery sells TA rings and there are several other suppliers. Your LBS should be able to get one at a very reasonable cost and the installation is easy.

I've made the same change on numerous 7,8 and 9-speed Shimano and other make road cranks (Ultegra, 105, Suguino, SR, and Sun Tour) and it always works well. It does slightly compromise shifting into and out of the granny ring and you won't be able to use the smallest one or two rear cogs with the granny but these are very minor disadvantages.

NoRacer

IMHO, perhaps you should work on your strength. That Trek looks like it comes with 52/42/30 crank w/11x32 cassette. If you can't get up a hill in the 30 x 32, you may need to do some kind of resistance training on [more hills] or off [weights] the bike.

mcoine

Here's mine with a 24 tooth vuelta ring:

rmfnla

Specialized makes a nice one in stainless steel that really holds up; I put one on my wife's bike.

I also swapped the 42-T middle ring for a 39 (yeah, I know; don't mix A and B chainringsrings... hogwash!) to ease the shifts and spread out the ratios.

Works like a charm.

europa

There's no doubt that eventually I won't be needing the lower gear to get up the hills around here, but isn't a bike supposed to take you where you want to go now? And what about if I decide to take a heavily laden tour? And while the hills around here are pretty darned nasty (even the hyper fit blokes consider the two culprits I'm thinking of a real challenge), there are worse. Besides, I'm in this game to ride bikes, not turn into a fitness junkie - to me, the fitness and strength is a side benefit.

Most importantly though, is the wasted gearing on the stock set up. Nine speed cluster on the back. Going from the lowest middle chainring gear to the granny, gives you only two extra gears with the third being a duplicate of the lowest middle chainring gear. Dropping to a 26, pushes that duplicate up one cog and gives me an extra low gear. Considering that I won't use the bottom two cogs on the cluster when in the granny, changing to the granny puts me right in the centre of the useable range on the cluster.

As I said earlier, it's worth doing as long as I'm not spending a lot to achieve it. And it sounds as if it's a goer. Thanks for the replies.

Richard

socalrider

Here is a link for the 26t chainrings.. I would also recommend a chain deflector like the 3rd eye or Jump Stop. The 3rd eye works fine but the jump stop looks a little more solid.. This keeps the chain from falling off when going to smallest ring.. when you put a real small ring like 24 or 26 this is more common.. I have used a 24t with my ultegra triple with no issues so far..

https://sheldonbrown.com/harris/chainrings/74.html

https://sheldonbrown.com/harris/derai...tml#deflectors

Al1943

The drop from the 42 middle to a 26 small would be huge. I would expect the shifting to be rougher, up and down.

George

I changed mine out to the Deore 26/38/48 and it's as smooth as you would want it. With the 26 I can just about climb anything and the 48 is all I need for down hill. I know some guys like 52s, but I'm comfortible with what I have. Good luck.

socalrider

I am going to try a 52/39/26 so there is 13t between by gears.. This should make for a little better shifting.

Indolent58

+1 - The Jump Stop works like a charm.

HillRider

Yes, it sure is.

Shifting isn't wonderful but it certainly is functional and the minor deterioration is shift quality is more than compensated for by the improved low gear. It's not like you shift into or out of the granny all that often. Shifting between the big and middle rings is unchanged, of course.

Another vote for the Jump Stop or Third Eye Chain Watcher.

europa

Thanks for the links boys. Now I know it's possible (and where to buy) I can save the pennies. And yeah, I'll get the Jump Stop while I'm at it.

Richard