folderfan550

I have a 1981 Trek 412 with original wheels. The rims are a bit beat up and don't take kindly to not-so-great road conditions so am looking into replacement options. I see that some pre-built 27"/630 wheelsets are available so am thinking that may be the easiest option if reasonably decent tires are available. Not sure if switching the bike to 700C/622 wheels is worthwhile unless there a compelling reason to do so.

Pompiere

Since you are looking at buying new rims anyhow, I would go with 622/700c. If your brakes have enough space to move the pads down 4mm, then switching to 622 wheels is easy. Then you would have more tire choices, including wider ones. If you stick with 27 inches, there are some good tires available, but the sizes are more limited.

The Golden Boy 

Exactly.

I changed from 700c TO 27" specifically to use a particular set of brakes.

However, there's just more tires in terms of sizes and choices... and bigger sizes.

If you had really nice 27" wheels at your disposal... that makes it harder, but as long as you're doing new wheels- do 'em 700C.

sanmi

As others mentioned, the only compelling reason is greater rim and tire choice. This comes with the potential cost of needing longer reach brakes. I've had success filing the slots for the brake pad posts to make just a little extra room. If you end up buying new brakes you'll ironically end up with fewer options for those with the 700c wheels because most modern brakes have recessed nuts. Here, too, I've had success drilling the frame and fork to accommodate modern parts. There are also more nutted caliper options available than 27" wheels and tires.

Pre-built 27" wheels are certainly easier if you are happy with the wheel and tire choices. There's really no other downside. If you wanted to modernize the whole bike, you'd need 700c wheels (or build your own around 27" rims).

Nice bike, by the way. Looks like you are ready to go the distance!

Aubergine 

FWIW, I have rebuilt the wheels in those old Treks using the original hubs and new old stock Rigida 27" rims, so the bike remained original. Panaracer makes nice tires for 27" wheels, and you can get some even better tires from Compass, so don't worry too much about keeping it at 27".

ryansu 

Just for clarity Limited tire sizes for 27" means 4 sizes which range from 27 X 1 (630x25) to 27 x 1 3/8 (630 x 37) so the real question is do you want to go smaller than 25c or bigger than 37c? and if you do want to go bigger can the frame handle it? If the answer is no to either question I don't see a compelling reason to switch to 700c. YMMV

The Golden Boy 

It's not JUST size, it's what tires are available. All tires of the same size are not equal.

Unless I'm missing something, Compass doesn't have 27" tires. If they did, I'd be all over them like flies on rice.

I have 2 bikes with Compass Bon Jon Pass tires- Ostensibly they're 35s. I also have a set of Swift Tire Sand Canyon 1 3/8" tires- which are ostensibly 37s. The Bon Jon Pass tires are NOTICEABLY larger than the Sand Canyons.

Tires can come in a dizzying array of tread, tread patterns, sidewall thickness, protection layers and all that... It would be absolute folly trying to list all the options for 700c tires.

But you can do that with 27" tires. One post. https://www.bikeforums.net/14517719-post1.html

And it's not a large post either. If you want "classic" looking tires- half of that post is out.

I was pretty much a 27" wheel homer. I had 2 700c wheeled bikes, one I changed to 27" and the other I'd run through a set of regular Pasela 28s, and then went with Pasela TG 28s. Then I got a set of 700c wheels with the Compass tires on it. I really like Paselas; they're great tires. But the quality of the ride of the Compass tires and the Paselas isn't really comparable. (granted, I eventually opted for TG/PT Paselas because that's what I preferred and now having "too many" bikes to ride and not enough time to ride, I don't wear out tires.) However, the Sand Canyon and the Compass tires should be comparable- but the Compass tires are still much nicer. (I haven't tried the Sand Canyon black wall tires with the higher thread count)

I've got some really nice 27" wheels- Phil, Avocet, Suntour, Maillard 600 & 700 level hubs and Matrix Safari and Wolber/Super Champion rims. It would be quite expensive to get wheels as nice as these- and still kinda expensive to get rims to put those hubs on. I'm cool with the 27" wheels and the selection of 27" tires- but if something were to happen to the wheel or rim- at this point, I'd replace with 700c.

Aubergine 

You are right - my memory failed me. I agree with you that the Compass tires are superior to Paselas, although the latter are still good tires.

ryansu 

As I said YMMV and I totally agree that for the really high end tires like Compass, if you can afford them, 700c is the only game in town. And I also get that their are other valid reasons to convert to 700c like; room for fenders or if you do want to go wider than 37c, you want to standardize your Road fleet on one wheel size etc.

I guess where I get cranky is when I hear the "your going to convert to 700c right? cause its just what you do" chorus as kind of knee jerk reaction, when I think for many, not all, situations 27" wheels and tires fit the bill just fine.

Putting away soap box.

On a side note I am looking forward to getting some of those Sand Canyon 27 x 1 3/8 tires to try out on my Passage which is currently running Kendas in that size.

DiegoFrogs

Without some other very compelling reason, I'd never buy a new 27" wheel or rim.

I suppose if the bike has cantilever brakes and they can't be made to work, that could be a good reason.

Sun still makes the CR18 in that size, classic, double walled and single eyeletted. Higher quality than the single-walled 27" stuff on every bike I've ever acquired.

The Golden Boy 

In this instance, where the OP is talking specifically about replacing the wheels- It's silly to keep going back to 27" without a reason other than 'that's what it came with.'

Otherwise I agree with you, as long as the 27" tires available meet your needs. (and really, they do for 99.9998% of people)


The Kendas I know of in that size are knobbys. You're going to love the Sand Canyons - Right now I have them on my 85 Trek 620 with 36 hole Super Champion/Avocet wheels. I'll have to see what I'm running for pressure, but 40 sticks in my head.

The Golden Boy 

Most of the new brakes won't adjust enough, but a lot of the older, upper level brakes like the the 981, 982, 983, 986 and 987 (and variants like Ritchey and XC Pro) as well as the Shimano MC-70, M732 and MT-60 have a LOT of adjustability.

I think a lot also depends on the bike, the distance between the bosses (my Schwinn Voyageur SP is 50mm between the bosses) and where those posts were brazed. As long as the pads are not pointing down when they hit the rim.


FWIW Velocity also makes 27" rims:

Velocity Wheels - Hand Made in USA

27" - 630mm

Aero Dyad Synergy Twin Hollow

(but it looks like only the Aero and Dyad have 36 hole options)

ryansu 

Kenda actually makes two tires in 27 x 1 3/8. The knobbies you mention are the K161 and the K40 a standard gumwall road tire which is what I am running currently.

Pompiere

I have a pair of the Kenda knobby tires in 27x1 3/8 but they actually measure closer to 32 mm vice 35. They are the same width as the 27x1 1/4 gum wall.

The Golden Boy 

If those K40 tires ride like the Kenda 1 1/4 tires, you're going to love the Sand Canyons!

folderfan550

I am thinking of going with CR-18 rims or something of similar width. Have not had a chance to look at the existing brake calipers. May look in the bins of a recycled bicycle place to see what I can find for hubs. I can build my own wheels. I'd keep the current wheels if I ever want to return the bike to original.

The Golden Boy 

If you're doing your own wheel building...

Flog00 has these hubs that I've been eyeing up... but have nothing to put them on....

https://www.bikeforums.net/classic-vi...ange-hubs.html