Linear recumbent tyre advice

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a.twiddler
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Joined: 4 Jun 2009, 12:17am

Linear recumbent tyre advice

Postby a.twiddler » 1 Jul 2020, 2:13pm

I've just acquired a Linear LWB recumbent. Frame appears sound, just needs tidying a bit. Previous owner has fitted a 700C rear wheel incorporating the original Sachs 3X7 hub which runs smoothly and quietly on the work stand, currently has a 700X42c tyre on it. I understand that the original wheel fitment was a 26". I am hoping that any Linear owners out there might give me the benefit of their experience on tyres. Is there any advantage to going narrower, or would It be as well to go for the same width when I replace it? (The sidewalls show signs of cracking). If I knew what the width of the original 26" tyre would have been, it would give a starting point.

As for the front, it seems very lightly loaded, and the existing 20 X 1 3/8 tyre has a distinct tread pattern, though again has some sidewall cracking. Would it be beneficial to go for something with a pronounced tread, in the expectation of more positive steering feedback, or would a more modern smoother pattern be OK? Also, wider, narrower, or the same width?

I've been riding conventional bikes for years, but this is a whole new experience for me. I would welcome any advice.

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Tigerbiten
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Joined: 29 Jun 2009, 6:49am

Re: Linear recumbent tyre advice

Postby Tigerbiten » 1 Jul 2020, 4:38pm

My take .........

On a recumbent because you cannot out of the saddle to miss the bumps, wider tyres with supple sidewalls run at a slightly reduced pressure will give you a maximum suspension effect.
Wide tyres with stiff sidewalls just sap energy unless run a high pressure.
Narrow tyres with supple sidewalls pinch puncture unless at high pressure.
And the higher the pressure the rougher the ride can/will be unless you are on perfect tarmac.

As for the front tyre, you don't have a lot of weight on it so very little traction.
I'd just go for a plain high grip tyre.
Unlike the back wheel of a tadpole trike, which suffers from a similar problem, your not going to put that much force through it so you won't wear it out that quickly.

YMMV ......... :D

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Cunobelin
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Re: Linear recumbent tyre advice

Postby Cunobelin » 1 Jul 2020, 6:20pm

Linear has a wide range of owners and designers, so over the year's wheel sizes have changed.

History of Linear


Depending on age, the weak point is the rear "Forks" the earlier ones were just aluminium (sorry Aluminum on the frame decals) blades and they used to be pulled across to the chain side and needed bending back to realign the wheel which caused stress cracks. Later models had a"U" shaped reinforcement This also stresses (pun not intended) the importance of making sure that the folding joints are secure before riding

Image

Later models had a more structured and reinforced design

Image

My first recumbent in 1990 was a Linear recumbent and I thoroughly enjoyed it before upgrading to a Peter Ross Trice
Last edited by Cunobelin on 1 Jul 2020, 6:33pm, edited 1 time in total.

recumbentpanda
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Joined: 6 Apr 2009, 12:13pm

Re: Linear recumbent tyre advice

Postby recumbentpanda » 1 Jul 2020, 6:25pm

Hi! My Iowa Linear rolls on 2” Schwalbe Big Apples on a 26” back wheel. You have to get the pressure right for you by trial and error, but I love the ride. Also the 1920s fat tyre look on the black frame makes it resemble a Mochet Velocar! :)

On a long wheelbase bent, the front wheel is always going to be lightly loaded. You just have to ride accordingly, and remember that contrary to an upright bike, the heavy braking is done with the back wheel.

a.twiddler
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Re: Linear recumbent tyre advice

Postby a.twiddler » 3 Jul 2020, 12:42am

Thanks for all your input.
I was aware of potential issues with the frame prior to buying and examined it minutely before parting with the cash. It is straight and no sign of cracks. Following the mention of the Big Apples I did some measuring after looking up the actual dimensions on the Schwalbe website and sadly have to conclude that they won't fit the frame on a 700C wheel.
I offered up a 26" wheel which I had in the garage and it is surprisingly small in diameter by comparison.
The width of the existing unknown brand nominally 42C tyre is actually 38mm. I measured up the 35C Paselas on my tourer and they are actually 35mm in width.I have not come across any Paselas wider than 38C. I note that Planet X have some deals on various Vittoria tyres but the max size available is 38mm, and as I have no experience of these I cannot say whether that would be the actual size or whether they would be smaller in reality. The search goes on for a 700 X 42C or maybe a little wider tyre with a high thread count, some puncture protection with a reflective band,
preferably at a discount price. Not asking for much really!

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Tigerbiten
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Re: Linear recumbent tyre advice

Postby Tigerbiten » 3 Jul 2020, 1:20am

You may want to look at the 42-622 Marathon Supremes.

I run the 42-406 version of that tyre on the front wheels of my bent trike.
I think it's a light supple tyre with reasonable puncture protection, I like them.
It's just a pity they they stopped making that size a couple of years ago.
The 50-406 big apple I run on the back is a lot stiffer/heavier tyre.
Due to the thicker rubber on the tread I get double the tyre life vs some lighter tyres.
That's not so important when riding around my home patch, but it does become important when I'm on tour.

YMMV ......... :D

a.twiddler
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Re: Linear recumbent tyre advice

Postby a.twiddler » 4 Jul 2020, 3:39pm

Hi Tigerbiten,
can you give me the actual widths of these tyres as fitted? Although I have a 700C on the rear and a 451 on the front so widths for these might vary between diameters and even batches of the same tyre from what I have read on various forums. Width is not likely to be a problem on the front as there is a limited range anyway for 451 but finding something like a 42C for the rear that isn't actually a 38, or a 44 or 45C that might be nearer a 42 or the reverse scenario buying a 45C (if such a beast exists) that is actually a 45! There is approx 49mm between the rear fork arms at the place where the widest part of the tyre would be. so the best bet would be something that is actually a 42 (whatever is written on it) or fractionally larger. that leaves space for the wheel going out of true, or any flex that might or might not take place, loose wheel bearing, tyre that won't seat properly, etc.
I seem to have fallen into the squelching morass of mythological tyre sizing where it is only safe to buy a tyre on the assumption that it will be smaller than stated until you actually fit it and then find that you have the exception that is the actual size that it states on the sidewall. A bit hard to argue with a retailer for a return when the tyre is the right size, but won't fit on your bike. Even if there was a list somewhere of tyres that matched their quoted size, it would still depend on the rim width. Mine on the 700C is approx 21mm across the braking surfaces, maybe 17 or 18mm
internally.
The search goes on, though I am bearing in mind the suggestions posters have made to date.

nigelnightmare
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Re: Linear recumbent tyre advice

Postby nigelnightmare » 11 Jul 2020, 9:31am

I have a 1992 Linear.
I think both wheels have been changed as it has 700c rear & 406 front.
I have Schwalbe Marathon 700-28 on mine and find the ride OK.

The front is lightly loaded & as others have said your MAIN brake is the REAR
I put clarkes 70mm Vbrake blocks on mine and it really improved the braking performance.

It also has a FER spoke drive dynamo on it that seems to work fine after I striped and cleaned/lubed* it


*Lightly lubed with silicone grease.
P.S.
I replaced the foam seat pad as mine had gone like yours.
You can get them from "The Bike Man" $$$ or as I did source one from a company that sells foam cut to size.
Sorry I can't remember where I got mine from But it was in the UK & they do different densities.

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Cunobelin
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Re: Linear recumbent tyre advice

Postby Cunobelin » 11 Jul 2020, 9:41am

nigelnightmare wrote:I have a 1992 Linear.
I think both wheels have been changed as it has 700c rear & 406 front.
I have Schwalbe Marathon 700-28 on mine and find the ride OK.

The front is lightly loaded & as others have said your MAIN brake is the REAR
I put clarkes 70mm Vbrake blocks on mine and it really improved the braking performance.

It also has a FER spoke drive dynamo on it that seems to work fine after I striped and cleaned/lubed* it


*Lightly lubed with silicone grease.
P.S.
I replaced the foam seat pad as mine had gone like yours.
You can get them from "The Bike Man" $$$ or as I did source one from a company that sells foam cut to size.
Sorry I can't remember where I got mine from But it was in the UK & they do different densities.



The 406 is a common conversion, there is a much larger range of tyres than with other 20" rims

I did this on the Linear and again on the 1994 Trice

a.twiddler
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Joined: 4 Jun 2009, 12:17am

Re: Linear recumbent tyre advice

Postby a.twiddler » 11 Jul 2020, 6:31pm

The front wheel has a plain alloy drum brake which looks very similar to the Sachs ones I had on an MTB in the 80s so I will stick with the 451 for now, as I've managed to find a Durano online for it. (Not arrived yet). The original front tyre is a Michelin Diabolo which while having plenty of tread has a lot of fine cracks in its whitewalls which look rather bleached and powdery.

The rear I have managed to identify as a Kenda 42C though the actual model is impossible to read amongst the maze of sidewall cracks. On the short rides I have had on it so far it seems to soak up the bumps though I've been rather more absorbed with stopping and starting and keeping on course at this stage. I'm trying to balance out being able to get some practice in versus the likelihood of the sidewalls giving out before I can replace it. The steering is very light and sensitive and responds better now I've started to treat it with a light touch.

For better or worse I've ordered a Vittoria Randonneur which was a good price with some some puncture protection. Some mixed reviews, it is hard to know what version it actually is until I see it as Vittoria have seemed to have a tendency to rename and re specify their tyres. A bit like Schwalbe I suppose. When is a Marathon not a Marathon? First choice would have been Marathon Supremes, but the budget is a little strained at the moment.

So hopefully I will have a light, fast grippy tyre at the front and something a bit heavier at the back without too much in the way of steamroller tendencies.

When I can ride a decent distance with unclenched buttocks I will be in a better position to evaluate the seat cushion!

The rear caliper brake as fitted had the blocks at the lowest limit of the slots. I have managed to lower the brake on the frame so that the new blocks are more comfortably placed. There must have been a different brake on it when the 26" wheel was in place. The new blocks are Britax. Not bedded in or been used in anger yet, quite possible that I will need to change them once I start getting comfortable with the bike, for something that can add a bit more bite to what is apparently a notoriously weedy rear brake set up.

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Cunobelin
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Re: Linear recumbent tyre advice

Postby Cunobelin » 11 Jul 2020, 9:25pm

For about a tenner, you can get off cuts of Memory foam which improves the comfort of the seat

a.twiddler
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Re: Linear recumbent tyre advice

Postby a.twiddler » 11 Jul 2020, 10:45pm

Thanks! That's useful to know.

a.twiddler
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Joined: 4 Jun 2009, 12:17am

Re: Linear recumbent tyre advice

Postby a.twiddler » 28 Jul 2020, 4:02pm

The beast is now up and running and I have had a longer ride or two and am getting to know its peculiarities. The Vittoria Randonneur is nominally a 700 X 42C but the actual width is 38mm. Nevertheless it has supple sidewalls and rolls well. I am experimenting with tyre pressures at the moment.

The front tyre is the original Michelin Diabolo and now it is cleaned up it doesn't look too bad. The previous owner stated that it is a 451 and indeed it has 20 X 13/8 marked on it which seems to be right. However, while checking tyre pressures today I found that it also had 37-440 (500A Confort) marked on it which would seem to contradict the imperial markings. Every reference I have found so far states that a 20 X 1/38 corresponds to a 251 rim size so I am a bit baffled. More so, as I already have a 20 X 11/8 Durano waiting to go on once I have to replace it. On the plus side, the current Michelin does look like it will last a while, but even so.... does this come under the category of "Strange French sizes"? I don't feel inclined to take the front wheel off and mess around with tyres at present though that might ultimately the only definitive way to find what fits. Might even have to get the drum brake rebuilt into a 406 rim eventually. I thought the 251 was limiting enough but something even more obscure? Dearie me.

I hope one of you knowledgeable folks out there can shed some light on this.

a.twiddler
Posts: 46
Joined: 4 Jun 2009, 12:17am

Re: Linear recumbent tyre advice

Postby a.twiddler » 28 Jul 2020, 4:32pm

The beast is now up and running and I have had a longer ride or two and am getting to know its peculiarities. The Vittoria Randonneur is nominally a 700 X 42C but the actual width is 38mm. Nevertheless it has supple sidewalls and rolls well. I am experimenting with tyre pressures at the moment.

The front tyre is the original Michelin Diabolo and now it is cleaned up it doesn't look too bad. The previous owner stated that it is a 451 and indeed it has 20 X 13/8 marked on it which seems to be right. However, while checking tyre pressures today I found that it also had 37-440 (500A Confort) marked on it which would seem to contradict the imperial markings. Every reference I have found so far states that a 20 X 1/38 corresponds to a 451 rim size so I am a bit baffled. More so, as I already have a 20 X 11/8 Durano waiting to go on once I have to replace it. On the plus side, the current Michelin does look like it will last a while, but even so.... does this come under the category of "Strange French sizes"? I don't feel inclined to take the front wheel off and mess around with tyres at present though that might ultimately the only definitive way to find what fits. Might even have to get the drum brake rebuilt into a 406 rim eventually. I thought the 451 was limiting enough but something even more obscure? Dearie me.

I hope one of you knowledgeable folks out there can shed some light on this.

(re submitted with editing)

Jdsk
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Re: Linear recumbent tyre advice

Postby Jdsk » 28 Jul 2020, 6:17pm

a.twiddler wrote:The previous owner stated that it is a 451 and indeed it has 20 X 13/8 marked on it which seems to be right. However, while checking tyre pressures today I found that it also had 37-440 (500A Confort) marked on it which would seem to contradict the imperial markings. Every reference I have found so far states that a 20 X 1/38 corresponds to a 251 rim size so I am a bit baffled.

Is that 251 a typo?

Jonathan