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Tyre questions

Derek Perry2020-09-09 07:05:42

Now then folks. Sorry for another tyre question but I have trawled the Tinternet and can't find any reference to my tyres.  took Dawes Discovery Twin which I believe to be around the 2005 era out on our first ride and noted it was quite wobbleyor Lefty/Righty as my wife described it and also quite noisey. So I started looking at tyres.

It currently has 26 X1.75 TIOG tyres on it. They are pumped up to the recommended pressures as stated on the tyre wall. I can't find any reference to this brand on the tinternet.

So my questions are - What does the 1.75 relate to and can I fit narrower tyres as they seem awfully wide.

Thank you in advance 

philip tregear2020-09-09 08:27:39

1.75 is presumably the width of the tyres i would guess in inches.

You can fit narrower tyres but i doubt this is the cause of any wobble. If anything fat tyres would reduce wobble

Possible causes

Rider error not well synchronized in pedalling distribution of weight etc. Practice will fix this

Front and rear pedals not syncronized

Loose bearings in fork, wheels or bottom brackets 

Loose mounting of saddles saddle stems or handlebars

 

Front and/or rear wheel not correctly mounted toframe

 

 

John Little2020-09-09 08:34:46

If you lift up and spin each wheel you should easily be able to see if there's any problems with the wheels - for example an untrue wheel or a tyre sidewalls bowing out.

You don't say if you're used to tandems - they can be a bit different to a solo if you're not... 

 

Jon Watt2020-09-09 08:48:13

Your tyres will be Tioga, presumably the 'a' has rubbed off.

Now given you've said the width is expressed in inches (1.75 is the width in inches) rather than cm and they're 26inch, I'd guess they're mountain bike tyres. Are they knobbly? That would certainly create some noise and instability. Assuming you want to ride on the road then yes, you'd be better off with some road tyres.

These would be a good bet, very robust and puncture resistant and can be pumped up a lot harder making things feel more stable  (but naturally, a harder ride).

https://www.wiggle.co.uk/schwalbe-marathon-plus-rigid-mtb-tyre

Matthew Stephens 2020-09-09 08:53:54

Welcome!

As above; it may be unlikely to be the tyres.

In answer to your question, the narrowest I would put on would be 28mm tyres - I have 28mm gatorskins, schwalbe marathon  or schwalbe durano plus on some of our tandems. Narrow tyres will be faster on roads. Obviously,  if you are going off road, you may want something wider. 

If the bike wobbles for seemingly no reason,  it may be just inexperience  - if the stoker pulls on the bars while pushing on pedals, this will significantly affect the steering & balance of the bike. The stoker needs to keep evenly balanced & have a light grip on bars.  On bends, the stoker needs to go with the flow & not fight against the bike leaning. 

A big/ high gear will mean more 'grinding'/ pushing which could affect balance. Try higher spinning gears to help avoid this until more experienced. 

I am an experienced tandem pilot but not stoker lol so this is what I have read, been told & have gathered on the front end...

Stephen Gray2020-09-09 10:04:25

Any movement from the stoker however slight can cause "steering input" Examples are:

taking one hand off the handlebars

turning to look behind (change of weight across handlebars)

trying to look past you if stoker is shorter (dittoj

leaning either way

My stoker doesn't like when other vehicles come past unless they give us a lot of room and if she doesn't know how close they are going to be she will lean slightly away from them (to the left) instinctively which steers the bike towards the gutter or verge. After many years, I know this might happen and brace accordingly but it still catches me unaware sometimes.

When negotiating any tight space or something that might be slippery (e.g. wet leaves, ice,gravel on the road) I give her warning that I need her to be still (no fidgeting) "Steady!" or ."Stay still please"..

Another good thing to do to help your stoker is to soft pedal before stopping pedalling. Your stoker will het used to this and know when you are going to stop pedalling so he or she doesn't get jolted. Never stop pedalling suddenly without warning (either of you).

If your tandem doesn't have a shock seat post for the stoker, I would strongly suggest you invest in one. The stoker takes more of a hammering from bumps than the pilot does. Even if you have a shock post at the back still call out "Bump!" If avoiding one is unavoidable. This will allow the stokeer to take some weight off the saddle and reduce jolting. 
Hope that all helps with more harmonious riding together. 

Stephen Gray2020-09-09 12:25:01

Sorry that should have beencall out "Bump!l if avoiding one is not possible.

Graham Capper2020-09-09 13:25:03

I wonder if the Dawes might have been fitted with different forks, handlebars or stem - is badly chosen these can produce a very fidgety ride.

Peter Hobson2020-09-09 13:32:32

Hi Derek,  tips from a mech. 26 is the diameter of the wheel the 1.75 is the width of the tyre.  the best tyres to get at the moment is Scwalbe Marathon tyres.  26 x 1.75.  tyre pressure i runmine at 70.  

it could be that your wheels are not true.if you need them truing drop me a line and you can come over to Winteringham and i will true them for you on my machine.  

Derek Perry2020-09-09 19:53:56

Checked the wheels, bearings etc and all is good. I suspect the wobbling was definetly my Stoker as she said she was enjoying her self on the back and having a good look around.

I am going to change my tyres as they look pretty worn and aged. I have ordered the Schwalbe Marathon Plus in the 26" X 1.35 size as recommended by Jon.  As said my current tyres are 26" X 1.75. What exactly is the difference and if I am going smaller can I reuse the inner tubes.

Martyn Aldis2020-09-10 09:18:09

Hi,

We have a Dawes Discovery Twin from 2001, probably a 2000 model and have done several tens of thousands of happy miles on her including an end to end in 2009. The frame is now the only original part of the bike from 2000. The rear wheel supplied was not up to touring with camping luggage. I think Dawes started using a better rear hub with proper 145mm spacing to match the frame shortly after our bike was made. Ours had a mid to low end Shimano Parallax hub spaced at 135mm - good for a solo.

We had one potentially very serious failure on our Discovery which was that the right hand fork blade fractured at the lowest part of the "unicrown" bend. Our mileage on this fork was something over 20,000 at the time. Your fork may or may not be of the same design. The fork had no taper and all the flex was at once point. I can't post a picture of the broken fork at the moment but will do so in a few days if you want.

We fitted a new set of Dawes tandem forks intended for disk brakes and these have been sound but they are very heavy and transmit all road imperfections. They also have a little more offset so the bike now has less trail than is ideal. We no longer use this bike for tours but still local ride.

We sometimes used 35mm tyres with the original forks but find 42mm or 47mm width works best for us with a strong preference for Marathon Supremes, We have found the basic Marathon has been prone to cut at the rim hook on the rear wheel especially if the tyres has been allowed to run at lower pressure. Once the rubber chafer has worn through the coarse carcass threads can cut into the alloy hook and this roughness in turn saws away at the threads. In spite of this at the moment we have a 47mm basic Marathon on the front at 75psi and a 40mm basic Marathon on the back at 100psi as this bike is now used for wet weather duty in the lanes where the extra bit of tread may help. The size difference adds back a tiny bit more trail which helps - in my head at least. I keep an eagle eye for the tell tail signs of stretch in the side wall as this is the first sign that the threads are failing at the hook. Once these tyres are gone I may splash out on Marathon Duremes if SJS/Thorn still has them.

The Marathon Supremes and Duremes have a lighter side wall than the Green Guard Marathon but a proper fabric chafer and we have not had a Supreme fail at the hook. There was someone who used to post here saying they had a strong preference for folding tyres for tandem use as the bead can stretch a tiny bit to sit right up to the hook while a wire bead tyre, if slightly under size, will wander at the hook under the over load of tandem use and start the whole wear process. Certainly we have had no failures at the hook with folding tyres including Vredestein Moiree, Panasonic RibMos and Marathon Supremes.

Supremes are expensive but in our experiece are a very good value tyre as they roll easily, have very good puncture protection, best comfort and last well. The grip from the compound is very good, unlike the Marathon City that came with the bike. We would regularly spin the back wheel with those on steep wet climbs.

The Dureme has more tread.

Tyres with big knobs for mud work are never nice on road. As far as the wobbles go I think other posters have covered all the obvious things. The captain does have to do a lot more arm work on a tandem than on a solo with constant little corrections while the stoker has to develop a kind of easy relaxed mode. Tandems with high trail are even more inclined to stoker steering - our Canondale RT2 wouldn't really work with an inexperienced stoker for this reason. Our Discovery is not our stiffest framed tandem but is very adequate in this respect, even for both to standing on the pedals. Although we like to both stand to boost over short climbs and for backside relief I do think the lateral loads are very hard on the bike.

Martyn

 

Stephen Gray2020-09-10 10:16:29

Good article on tyre widths here.

https://bike.bikegremlin.com/285/bicycle-tyre-dimensions/

Whether you can re-use the inner tube depends on what size tube is in there. My guess is that it will be a pretty hefty inner tube and probably too big for your new tyre. The tube should have some dimensions on it so that will give you a clue. If you are not sure just inflate the tube until iit takes shape but no more than that and then compare with the new tyre. If it is narrower than the tyre then it will probably do. If it is fatter than the tyre then you probably need new tubes. Obviously also check the condition of the old tubes before re-using. 

Tim Goffe2020-09-10 18:58:47

MTB tyres for tandems

Hello,

We have a Gepida Thoris e-tandem which is a wonderful successor to our (also much loved) Thorn Adventure tandem. We really prefer riding the quiet country lanes, forest roads, tracks and bridleways and would like to use more suitable (MTB?) tyres for this rather than the standard issue Schwalbe Energisers, size 622 40C. I think we could go up to size 622 x 50 if we remove the mudguards so I have 2 quiestions, please.

  • Does anyone hav experience of fittingMTB style tyres on the Gepida?
  • Can anyone recommend any tandem suitable knobbly MTB tyres, size 622 x 50C?
Thanks, Tim