harry00

I am researching wheels for my bike as I wish to buy a new set.
It is an an old raliegh pursuit with 18-23 tubing. At the moment it has 27x1.25 wheels.
I wanted to put 700cs on due to the increased wheel set and tyre choice.
I've done a lot of online research to see if it will work, many say yes, many say no.
I tried my friend's 700c wheels and they seem to fit,
however I am aware I would need to buy and extended brake.
So I decided to buy some 700c wheels and now I'm wondering if my bike would take a 'cassette' type wheel,
I know this would mean buying a new cog set.
Would I need a new rear derailleur?
Is it even possible to fit cassette wheels on my bike?
Any help would be appreciated.
Thanks, Harry.

Retro Grouch 

Measure the distance between your rear dropouts.

You didn't say how old your Raleigh is. If it's kind'a old, the dropout spacing will be 126 mm. If it's real old, they'll probably be 120 mm. Modern wheels will be 130 mm. Four millimeters isn't very much, lots of guys just ignore the difference. 10 mm is a bit more and will probably make it necessary to spread the stays. Your existing derailleur will be the least of your problems but, if you spread the stays, you'll want to realign the dropouts so that they are parallel again.

I'd also borrow the 700c wheelset again and measure how much brake reach you need. I'd want to make sure of sourcing the brakes that you need before spending money on new wheels.

Speaking of which, I also think it would be a good idea to price out the whole project before starting. New wheelset, new tires and tubes, cassette and maybe chain and the first thing you know, you're talking real money. What you'll end up with is an old bike that has a few new parts. If that's what you want fine, I fully understand.

On the other hand, for probably not much more money you may be able to buy yourself a brand new bike. Every single part will be brand new and every single part will have been designed to work with every other part. You'll also get a new bike warranty.

sreten

Hi,

No good reason most brakes wouldn't still fit, its
only 4mm in each slot, most have miles more.

rgds, sreten.

fietsbob

If it is old and 120 wide, consider another rim rebuilt on a 3 0r 5 speed internal gear hub.
no derailleur needed..

27" wheel frames also can be converted to 650B [bit smaller rim but 1.5" wide tire.. ]

current cassette rear hubs are on 130 &135 wide axles.

trying to upgrade an old frame to use the latest parts will cost more
than just buying a New, modest pricepoint whole bike.

gyozadude

+1 on checking the brake reach requirements, especially if you have an old touring bike with cantilevers. My Bridgestone 700 has ISO 630 (27 inch) rims, and the cantilever brake bosses are brazed on high on the stays and the fork. They were designed for super short stack Dia Compes which don't work that well compared to newer cantilevers, but those brakes rarely fit. I've tried a lot of Tektros, Shimanos, etc. and only two Shimano Models actually have low enough reach. If I were to try 700c wheels, then there wouldn't be a brake in existence. Sort of a design issue on that model and there have been a few times, I was fed up and almost hacked the bosses off and rebrazed them on lower. But that was going to be so much work, I chilled and thought better of it.

Even if you have center pulls or standard caliper brakes, you may want to check if the reach is sufficient. If you have medium-long reach (49-59mm) reach calipers and are already near the max extension, you won;t like the choices you have in super long reach dual pivots and the mechanical advantage will make you nostalgic for the days of dept. store BSO brakes.

Kimmo 

One option to consider is a 700c fork, which will allow you to have proper braking where you need it.

sreten

Hi,

Tyre choice is limited, but you can still get decent types :

https://www.sjscycles.co.uk/tyres-27-(630)-dept203_pg1/

rgds, sreten.