Max tyre pressure on steel rims

[Bodhbh]

I've read that at high pressures tyres will blow off old steel rims. What kind of pressure we talking about?

Longstory - I have an old Raleigh Twenty/Stowaway I'm gradually upgrading. My main area of irritation with it atm, is the stock white-wall 20x1-3/8 tyres, which seem a bit pants, are only rated for 50psi and squirm a bit under my fat arse. I'll probably replace with some BMX tyres which won't go much higher, but considering some 28-451 Duranos which would be 90-120psi...

 

[Rickshaw Phil]

Don't know about the pressures but like you I understand they have to be quite a bit lower on non-crotched rims.

Those BMX tyres almost certainly won't fit as standard BMX size wheels are 406mm rather than the 451mm for old British shopping bikes (both are called 20 inch even though they are different sizes). I seem to recall that @tyred had one of these or similar and may be able to advise.

 

[Bodhbh]

Don't know about the pressures but like you I understand they have to be quite a bit lower on non-crotched rims.

Those BMX tyres almost certainly won't fit as standard BMX size wheels are 406mm rather than the 451mm for old British shopping bikes (both are called 20 inch even though they are different sizes). I seem to recall that @tyred had one of these or similar and may be able to advise.

Cheers! Regarding the BMX tyres, I've looked into it, and there are also a few BMX tyres in 451mm. Not many but some - Tioga Power Block, Maxxis DTH. I believe it's a racing size or something. But yeah, 451mm is a pain to find tyres in. Ideally I'd like something like 35mm Marathon's but it's not happening!

 

[tyred]

No Sir! BMX and Raleigh Twenty tyres may be both 20" in theory but they are different sizes.

20 x 1 3/8 (or some other fraction) are 451mm under modern sizing schemes.

BMX tyres will be 20 x 1.?? are as stated 406mm and definitely not compatible.

Contrary to popular belief, tyres don't need to be rated at 100+ psi to be any good. 1 3/8" tyres are quite wide so can be run at lower pressure and will roll just fine, in fact they probably roll better on normal road surfaces. Raleigh Record tyres aren't the best but others are available, I think Schwalbe & Continental make tyes in this size. On a 20" wheel, I would avoid high pressure tyres as that is what provides the suspension in these bikes (unless you yourself are very light. If you 9+ stone, HP tyres would be bone jarring in this size imo). Moulton used small high pressure tyres but they had suspension.

 

[Bodhbh]

No Sir! BMX and Raleigh Twenty tyres may be both 20" in theory but they are different sizes.

20 x 1 3/8 (or some other fraction) are 451mm under modern sizing schemes.

BMX tyres will be 20 x 1.?? are as stated 406mm and definitely not compatible.

Contrary to popular belief, tyres don't need to be rated at 100+ psi to be any good. 1 3/8" tyres are quite wide so can be run at lower pressure and will roll just fine, in fact they probably roll better on normal road surfaces. Raleigh Record tyres aren't the best but others are available, I think Schwalbe & Continental make tyes in this size. On a 20" wheel, I would avoid high pressure tyres as that is what provides the suspension in these bikes (unless you yourself are very light. If you 9+ stone, HP tyres would be bone jarring in this size imo). Moulton used small high pressure tyres but they had suspension.

I know most BMX tyres are 406mm, but there's one or two in 451mm (i.e. 20x1-3/8) - Maxxis DTH are. But, cheers, I'll have a look what Conti do, as I'm not so familar with their range. I don't really want anything particularly high pressure or narrow - it's an about town bike to do errends and shopping on - but the combo of lowish pressure and lowish volume at the back feels odd to me. I'd prolly be happy with 70-80psi, which is what I run on the commuter with a similar volume.

Ultimately I'll get some new wheels sorted and may go for 406mm + plus some nice plush 20 x 1.75s to keep the geometry similar and give a nicer ride, but cash flow atm. Those old steel wheels weigh a frigging ton.

 

[Archie_tect]

60 psi on my old Dawes's 27x1-3/8 tyres runs nicely.

 

[tyred]

I know most BMX tyres are 406mm, but there's one or two in 451mm (i.e. 20x1-3/8) - Maxxis DTH are. But, cheers, I'll have a look what Conti do, as I'm not so familar with their range. I don't really want anything particularly high pressure or narrow - it's an about town bike to do errends and shopping on - but the combo of lowish pressure and lowish volume at the back feels odd to me. I'd prolly be happy with 70-80psi, which is what I run on the commuter with a similar volume.

Ultimately I'll get some new wheels sorted and may go for 406mm + plus some nice plush 20 x 1.75s to keep the geometry similar and give a nicer ride, but cash flow atm. Those old steel wheels weigh a frigging ton.

You will (probably) need longer reach brake calipers to use 406s.

 

[tyred]

I've no idea what I put into my 20 x 1 3/8" as I have Woods valves but just so they pass the thumb test.

 

[DaveReading]

When I bought my first track pump, I made the mistake of pumping up the tyres on my steel-wheeled racer to the pressure marked on them.

Fortunately I was only a few hundred yards from home when the front one blew clean off the rim.

 

[Bodhbh]

Forgot about this, but cheers for the responses. If I'm honest, and after doing the commute on it a couple of times, I think some of the 'squirminess' I'm feeling is down being un-used to the short wheelbase/chainstays of the bike.

When I bought my first track pump, I made the mistake of pumping up the tyres on my steel-wheeled racer to the pressure marked on them.

Fortunately I was only a few hundred yards from home when the front one blew clean off the rim.

Gah...I assume this results in the inner immediately blowing out and an off?

 

[Tim Hall]

Like @Rickshaw Phil says, the limit will be down to rim design. Today's rims are hooked (or crotched, as he says), so the bead of the tyre has something to locate in, when pressed outwards by the tyre pressure. Older rims are smooth. We discovered the difference once on the IOW Randonee, when the Cheating Czech blagged my spare tyre to put on his knackered old steel rimmed Peugeot. The tyre blew off, taking the last spare tube with it. We jury rigged a repair involving a handful of patches and lots of insulating tape.

 

[Bodhbh]

Like @Rickshaw Phil says, the limit will be down to rim design. Today's rims are hooked (or crotched, as he says), so the bead of the tyre has something to locate in, when pressed outwards by the tyre pressure. Older rims are smooth. We discovered the difference once on the IOW Randonee, when the Cheating Czech blagged my spare tyre to put on his knackered old steel rimmed Peugeot. The tyre blew off, taking the last spare tube with it. We jury rigged a repair involving a handful of patches and lots of insulating tape.

I checked the rims, they are smooth.

I'll leave this bike be for the time till I have some cash to blow....tyre upgrade = rim upgrade = wheel + hub upgrade = drivechain upgrade = framestrip and powdercoat (because) = $$$.

 

[Mile195]

I know very little on this subject, but just to give you my experience I used to have an old Peugeot racer, and before that I used an old Dawes road bike. I used to pump both up to 60psi and nothing blew.