Help identifying Raleigh frame

[ti-raleigh]

Quick question; the seat post is a modern FWE item which would make it 27.2mm - my eyes could only resolve 27mm on the ruler.

Can I presume that vintage seatposts from 26.8mm and up will fit?

Does this mean the seat tube outside diameter requires a 32mm band-on front derailleur?

Russ

Hi Russ, that's my TI-Raleigh SBDU link you shared earlier. Your frame is from Raleigh's Special Products Division. The 'E' is from 1994 based on what is known about that system. Raleigh had a facility at Nottingham called the 'Lightweight Unit' from 1981 to 1990. That unit used the older and more well known 'W' serial number system, but the unit and the old SBDU were replaced and the Special Products evolved, starting with 'A' numbers in 1990.

If the frame is 531 Competition tubing and uses the standard single butted 531 seat tube then the seat pin diameter will be 27.2mm - the outer tube diameter for a front derailleur should be a standard 28.6mm

Cheers
Neil

 

[midlife]

Hi Neil

Which link was that?

 

[russ.will]

This one! And bloody marvellous it is.

@ti-raleigh Thank you Neil for that page, confirming what I think I'd worked out and for the additional info. If I read your post correctly the outer diametre minus the inner diametre and divided by two, gives a wall thickness of 0.7mm? Strewth. Go easy on the torque wrench then....

I guess that also answers whether I can use Campagnolo Veloce 10spd Groupset; yes, with a 28.6mm clamp to suit a braze on front mech. Not the neatest, but in my head I'm looking to maintain a 'vintage' look, but using modern mechanicals and needs must. The Halo Retro 6D wheels are ordered and Groupset, stem(s) and seat are next.

I'll wait until winter to take it apart and get the frame done. I'm thinking chrome lugs, chainstays, dropouts and forks, but what colours in between...

Russ

 

[midlife]

Ah, I guess Neil is 'originalshinkicker' on Retrobike?

 

[ti-raleigh]

Ah, I guess Neil is 'originalshinkicker' on Retrobike?

Yes that's me - this topic showed up as a referral on my blog so I had a look

 

[ti-raleigh]

This one! And bloody marvellous it is.

@ti-raleigh Thank you Neil for that page, confirming what I think I'd worked out and for the additional info. If I read your post correctly the outer diametre minus the inner diametre and divided by two, gives a wall thickness of 0.7mm? Strewth. Go easy on the torque wrench then....

I guess that also answers whether I can use Campagnolo Veloce 10spd Groupset; yes, with a 28.6mm clamp to suit a braze on front mech. Not the neatest, but in my head I'm looking to maintain a 'vintage' look, but using modern mechanicals and needs must. The Halo Retro 6D wheels are ordered and Groupset, stem(s) and seat are next.

I'll wait until winter to take it apart and get the frame done. I'm thinking chrome lugs, chainstays, dropouts and forks, but what colours in between...

Russ

There are constant debates on seat pin size and tube diameter and distortion of the seat lug due to heat which affects internal diameter. The outer diameter minus the inner wall thickness x 2 doesn't actually match the seat pin size. What I found works for me. A 531c seat tube is 0.8mm/0.5mm single butted - so 0.8mm at the BB end and 0.5mm at the seat lug end (that 0.5mm wall thickness is the same as 753R and 531P and this is why 531c/753R & 531P all accept a 27.2mm seat pin).

That 0.5mm can also be quoted as 0.55 or even 0.56. I found that the following guide works for all my frames...

• Imperial 28.6 diameter with 0.5mm seat tube takes 27.2mm (531c/753R/531P)
• Imperial 28.6 diameter with 0.7mm seat tube takes 26.8mm (531 ST)
• Metric 28.0 diameter with 0.3mm seat tube takes 27.0mm (old 753 lighter gauge tube)
• Metric 28.0 diameter with 0.4mm seat tube takes 26.8mm (old 753 heavier gauge tube/531SL)
• Metric 28.0 diameter with 0.5mm seat tube takes 26.6mm (Metric 531c)

 

[rogerzilla]

Seatposts have to be the right size. A 27.2 can't replace a 27.0, and nor can a 26.8.

Adding to the post above, 531C, on paper at least, should take a 27.4mm post. 28.6mm seat tube, 0.5mm walls, 0.1mm all round for clearance as it is NOT an interference fit. 28.6-(0.5+0.5+0.1+0.1) = 27.4. Tony Oliver indeed used 27.4 posts in 531C frames but his were silver-brazed at low temperature.

Most 531C frames take a 27.2 post because the heat of brass brazing distorts the seat cluster. After brazing, a 27.2 reamer is put down the tube. A 27.4 reamer would possibly make the tube wall too thin where its diameter is reduced by the distortion.