SurferRosa

I can use a 14-28 rear cluster with my 42/52 cranksets, but am limited to a ...

13-25t cluster with my 53/39 crankset.

'Cause I use short cage Campy rear mechs.

Not "just sayin'."

Just ridin' and meanin'.

70sSanO

Not to derail this, but I ran the same cogs, but then got a Shimano 11-30 8 speed and put them together to build a 14-16-18-20-23-26-30-36. I found the 32 to 36 was a bit close for a bailout.

John

Amelio 

that sounds interesting but to me the 11-30 seems great in itself. Is the freehub too large to accommodate the 11 tooth? I only ever see this vintage bikes with a 13 or 14T for the high gear.

good feedback thank you!

tkamd73 

No answer to your question, but really nice bike!
Tim

Amelio 

Thanks Tim, I really appreciate it! There’s just something about her that draws me in!

tkamd73 

That bike could be the poster child for CV, thanks for sharing!
Tim

ThermionicScott 

An unsoliticed example of what could be done... I built up this Shimano 105 crank with a Shimano 4503 50T big ring and Sugino 38T inner ring. It dropped the overall range nicely from 52/42 and shifted really well. 4503 parts are a bit less available now, but you can still find that big ring easily in 3503:

genejockey 

Dura Ace and Sante Uniglide freehubs could handle an 11t, by making just the threaded part smaller, so those freehubs need their specific threaded smallest cogs.

52telecaster

when I build 7 speeds I usually go 12-14-16-18-22-28-36. When it's time to go low you really want to get there. The previous cassette is on a bike with 46-26 chain rings so 26-36 is pretty seriously low.

verktyg 

Amelio Some starting points with explanations and terminology...

Some photos lifted from Sheldon Brown's website RIP... The teethed things that the chain rides on are called Sprockets or Cogs. Sprocket is more proper technical term.


Amelio Your bike has a Shimano 6 speed Freehub with 13-28T Uniglide Cassette.

The width over the lock nuts on the hub axle is 126mm and that's the spacing or distance between the dropouts (unless someone has modified them).

Uniglide refers to the shape of the teeth on the sprockets. Shimano replaced that design with Hyperglide sprockets in the late 80's so Uniglide cassettes and getting rare and expensive.

Uniglide Sprockets have "twisted Teeth" while Hyperglide sprockets have "ramps" to aid shifting.

Some 6 speed Shimano Freehubs can take a 7 speed Cassette. 7 speed Cassettes with 30T or 32T are more readily available but need some minor modification to fit your Freehub. That's where it can get sticky for a first time "modifier"



In addition to 126mm wide hubs, 130mm wide became the standard for Cassettes with 7, 8, 9, 10 & 11 Sprockets, referred to as 8 Speed Cassettes and so on.

Rather than reinventing the wheel the OBVIOUS solution is to help you get some lower gears to meet YOUR cycling requirements without spending an arm and a leg.

My first recommendation is to get a smaller front Sprocket, called a Chain Ring.

Shimano introduced cranks that could use chainrings as small as 39T back in the early 70's. This was opposed to the Pro racing designed Campagnolo style cranks that were limited to a 42T small Chain Ring.

A 39T will give you about a 7% lower gear. A 38T Chain Ring will give you about a 10% reduction from a 42T but... it requires a slight modification for the 38T to fit on many Shimano cranks.





You will need to file about 2mm off of the ends of the areas on the crank where the Chain Ring mounts on the "Spiders" or "Webs" for enough chain clearance with a 38T.

Your Shimano rear derailleur should be able to handle a 38T to 39T small Chain Ring with a 30T or 32T Sprocket but you will probably have to add a link or two to the chain.

Come back after you digest this info...

Next, your Araya rims to have a hook or lip on the inside. You can feel it with your finger. It doesn't take much to grip the wire bead on the tire.



verktyg

pastorbobnlnh 

As 52telecaster mentions (thanks for posting your picture), and as I inferred in my first response, your wheel is not equipped with a freewheel, but instead a freehub and Shimano UG cassette. This opens you up to gearing possibilities which are quite affordable.

Here's how (you will need a Dremel or other grinding tool, a 9 speed HG compatible cassette which does not have a sprocket carrier, and possibly a UG 7 speed threaded sprocket)

1. Remove the smallest threaded sprocket with the two chain whips as directed above and keep
2. Remove the remaining five sprockets of the cassette, and set aside for now (the spacers might be needed later)
3. Examine the back your replacement HG cassette and look for the screw or rivet holding the cassette together, remove it or grind off the head of the rivet and separate the sprockets and spacers

1. Select the 6-7 sprockets (not the smallest two) you want to use and locate the one wide spline (in the 5 o'clock position in the above picture)
2. Using the Dremel, grind the wide spline to the width of the other splines, making certain you do it on the same side for all sprockets (in the above picture you'd grind the right-hand side as you look at the cassette)
3. Slide the modified HG sprockets on the UG freehub body and use the 9 speed spacers
4. You should be able to install at least 6 HG sprockets and possibly 7 HG sprockets, leaving enough space for the threaded small UG sprocket to secure the cassette to your freehub (as pictured in your original set-up, the threads from the 13T sprocket should fully engage the UG freehub body)

Hope this is helpful, and it should save you from purchasing an expensive new UG cassette (just check ebay). As an added bonus, your friction shifting will be improved by the ramps on the HG sprockets.

Miele Man

If you don't have two chainwhips but only have one chainwhip you can still unscrew that smallest thread on Uniglide cog. Put the wheel on the bike. Shift the rear so that the chain is on the largest sprocket. Put the chainwhip on the small threaded on cog with the handle of the chainwhip pointing away from the frame. Push down on the chainwhip to unscrew the threaded on sprocket. That threaded on sprocket unscrews counter clockwise.

A 39 teeth chainring will make a difference.

If you want to go to index shifting it'll get expensive fast unless there's a bicycle co-op near you where you can get the needed components cheap.

For index shifting you require an index compatible rear derailleur and index shifters. It's also better to use the special SIS (Shimano Index System) rear derailleur cable housing.

You also might have the Shimano specific downtube shifter braze-on mounts that don't work with the more common shifter mounts.

I've had people come to my place about an hour drive from Toronto to do some work on their bike where they didn't have the proper tools. You're welcome to do that if you want to. Just Private Message me if you'd like to do that.

One nice thing about Uniglide sprockets is that when any of them other than the last threaded on one wear out and the chain starts to skip, you can reverse the cog and use it for many more kilometers/miles.

Cheers

52telecaster

Man you guys are a terrific resource!

Amelio 

What this man said, thanks everyone!!!

Miele Man

I've had a lot of help with getting parts from members here or links to sources for inexpensive parts. I just received a pair of Campagnolo Super Record non-aero gum rubber hoods from Serbia that only cost $24.00 USD with free shipping.

Cheers

canklecat

Going from a 42T to 39T or 38T chainring will help. When I got my Ironman in 2017 I rode it as-is for several months -- 52/42 chainrings, 7-speed 13-24 freewheel.

But as I tackled the roller coaster terrain west of town -- lots of short, steep climbs, but no mountains or even long gradual climbs -- I discovered my 60something-year-old legs that felt fine on the multi-use paths and city rides where it's flat... weren't so happy on the more challenging rural terrain.

At first I switched to a 13-25 freewheel but still wanted a bit more help, and tried a Vuelta brand 39T small chainring. That worked fine for about a year. Then I was hit by a car, setting back my conditioning for awhile. So I switched to a Vuelta SE 50T big ring (ramped and pinned, excellent value), Vuelta regular 38T chainring (the smallest that will fit some 130 BCD cranksets) and 13-28 SunRace MFM30 7-speed chromed freewheel. That really helped on my long grind toward regaining fitness lost during rehab.

While I'm strong enough again to handle the original 52/42 and 13-24 setup, I prefer the more relaxed ride of the Ironman with the 50/38 chainring and 13-28 SunRace MFM30 freewheel.

And the spacing feels about right. Some combos of chainrings and freewheels/cassettes suffer from odd spacing. For example, my mid-2000s era Diamondback Podium carbon fiber frame is currently set up with a hodge-podge of components from the bin, including the original Ultegra 6700 53/39 chainring (from the Shimano 10-speed group), a SunRace 11-28 chromed (or maybe zinc plated?) 7-speed cassette, and MicroShift R7 7-speed brifters. Eventually I'll build that bike up properly to a 10-speed, but some components are still in short supply due to the pandemic. Anyway, I dislike the spacing of the 11-28 cassette in 7-speed. Some awkward jumps that make it difficult to transition smoothly over rolling terrain -- my cadence veers from 60-100 rpm trying to maintain a steady pace. And I do a lot of double-shifting between the chainrings and cogs trying to find the sweet spot.

So I can recommend a Vuelta 50/38 chainring and SunRace MFM30 13-28 7-speed setup because it suits me. (Or SunRace MFR30 13-25 for flatter terrain or stronger engine.) But someone else might find another gearing combo suits them better.