ADVICE ON TANDEM TYRES PLEASE

[MikewsMITH2]

I have recently resurrected our old 1979 Peugeot Tandem for my wife and I to do a 100K ride in a couple of weeks time. I am working to get the bike reliable after years in storage. However I'm concerned about the tyres which are now about 20 years old. They have stood up to 3 or 4 long rides of about 50k each without problems but failures on the 100K would be a disaster.

The rims are steel and marked 28x 1 5/8 x 1 1/8 700C. They measure 26.7mm from tim to rim across the outside.

The current tyres are Nutrak Marathons there is no size marked on them.

Question is can I use 700x28C section tyres for a faster ride or should I use 700x32C ?

[richardirving]

Your measurement states 26.7mm - just over an inch in old money. I assume you mean inches. That equates to 678.2mm which seems large for a 700c, but I believe the key dimension you should be looking for is the bead seat diameter or ETRTO size. For a 700c tyre this should be marked as 622, for older 27x 1 1/4 it would be 630. 650B would be 584 and 26" is 559. You may find it engraved very faintly somewhere on the outside of the rim or moulded onto the tyre tread edge. Perhaps the easiest thing to do is to try the tyre on a rim of known size (a friend, perhaps or the local bike shop if it is old fashioned and helpful) namely a 700c/622 rim and if it pops off easily when pumped up then you may be looking at a 27 1 1/4, but I think that is unlikely.

[MikewsMITH2]

They are definitely 700C. Not sure of width though,. CTC shows equivalent of 28 x 1 5/8 x 1 1/8 as 700x28C. Fitted tyres look wider than 28 though

[gaz]

Sheldon Brownmay have the answer.

Scroll down the article to find opinion on nominal tyre width for internal rim measurement. Also confirms that it's 700C but you're not worried about that bit anyway.

Good Luck.

[speedsixdave]

The answer is 700x32s. The issue is that you've got a lot of weight on the tyres (with no disrespect intended to you or your lovely wife!), and the narrower the tyre the smaller the air pocket, so the more likely you are to get pinch flats from potholes, especially at the back. They will also be rather more comfortable. I'll bet you a shiny pound you can't tell the difference in speed on a tandem between 28s and 32s

On that note, your wife will love you more if you get her a suspension seatpost. They're only about £15 for a Tranz-X or other budget - but functional - brand, and the drastic reduction in earache coming from my stoker made that probably the best value £15 I have ever spent. However it does mean you will have to establish what size seatpost your Peugeot takes - not always as easy as you would hope.

Hope you enjoy it!

Dave

[MikewsMITH2]

What about 30C at back asnd 28C at front?

[jimcrosskell]

Make sure you have clearance for the frame, mudguards etc before going too wide. Remember that what looks ok on the stand may well catch when the wheel flexes under the strain of jomping up a hill with luggage on.
Backwinds forever........

[PW]

Nutrak Marathons were a good tyre - 20 odd years ago! IIRC they were sized 700X32C, if you wanted narrows there was another, lighter tyre in 28 or 25C. (Nutrak Tracer??) So I think it used to have 32s so why not try them again? Tandems are best with a stronger tyre, leave the super light stuff for the solos.

[MikewsMITH2]

OK thanks to everyone for the advice I have ordered a pair of Schwalbe New Marathons in 700x32 with new tubes and rim tapes. I'll let you know how they go!
Thanks Again,
Mike

[Cyril Haearn]

OK thanks to everyone for the advice I have ordered a pair of Schwalbe New Marathons in 700x32 with new tubes and rim tapes. I'll let you know how they go!
Thanks Again,
Mike

How did they go?

[rjb]

If they lasted 10 years then they would not have done many miles! I could never make my tandem 700c tyres last more than 4000 miles before they were worn down to the canvas, about 8 months.

[gaz]

How did they go?

Round and round, of course .

[MikewsMITH2]

They were often flat at the bottom

[tim_f]

Question is can I use 700x28C section tyres for a faster ride or should I use 700x32C ?

A 28c tyre will not necessarily give you a faster ride.

Collective wisdom on this has changed in recent years. Wider and lower pressure can be faster on a real world road surface.

[MikewsMITH2]

Wider tyres at lower pressure are only faster if the tyre is more flexible. Schwalbe Marathons are not flexible.