3.5" tubeless tires

[ex-Gooserider]

I forget the exact size, but it is under an inch, I think it's 15/16".... It also needs to be a deep-well type, preferably thin wall, but most deep-walls are thin wall by design. (Cheap sets of deep wells can be purchased at Harbor Fright pretty cheap)

Most forks I've found don't need a wrench on the bottom, as the shaft is welded to the fork, or in some cases the head is held captive by the sides of the fork...

If you do need a wrench, a standard spanner / adjustable probably won't fit well, so you would need a thin wall socket and breaker bar, and even that might be tough to get to fit. My approach would be to use a flat blade screwdriver or pry-bar and stick it in between the bolt head and the side of the fork so that the bolt head cams tight against it.

ex-Gooserider

[expresso]

yes you can use a screwdriver - now that i think of it - i think that was used on mines also when i changed the forks - screw driver to hold it from turning

i think 15/16 sounds right - i didnt find mines yet - if when i do - i let you know -

[hobie1dog]

The nut on top was a 5/8-18 nylok nut which measures 15/16". Problem is the way they designed the top of the nut well. I called 4 places and nobody had a thin wall socket. I went and got a Plumbers shower valve socket set since I remembered how thin the walls were on them, one of the sizes was 31/32 which is just slightly oversized, but it worked good for my specific application. My older brother is visiting me and provided the wrenching. We drilled out the stock 5/16" holes in the caster forks for the new 10mm bolt. It took 7 washers between the inside of the caster forks to the wheel bearing (6 of the 1/8", and 1 of the 1/16" thick . That made up the 11/16" space, as I had no one to machine a SS spacer, so I had to do the shade tree engineering method. There is only 1/4" or so of clearance between the tire and the inside of the fork. With the tire wobbling slightly, sometimes likely 1/8" of clearance.
It raised the front of the chair so much that my recline wouldn't work, so I knew that the mercury switch was likely locking it out. It was held on to a small bracket with cable ties, so I clipped the rear one and installed a new cable tie under the switch that pulled the switch up to make it functional. The other bad part of the installation is now the anti-tip wheels are making contact with the ground
I need bigger diameter tires on the rear. I read that the shocks could be adjusted with a spanned wrench which will lower or raise the back end.

[expresso]

If you can - take pictures of what your doing and changes - effect - solutions etc, - its always good for yourself to look back at also and i love to see them also - on the 646 - or 636 etc - i dont think those shocks raise the rear - i could be wrong

the tires i used did raise my rear - maybe its something you can look at it - they fit my stock rims - 3.50 - 8 - but had to raise the fender up a bit - they fitted with no washers on my chair - that would raise the anti tippers -

mines were off the ground to start with - -

are your anti tippers off the ground now or before you did any work ?

i forgot - you have a new 636 chair ?

[snaker]

I just found a shop selling sealants. Its brand is PFERD (German brand? UK made?).

Each can is 430ml. The seller said it is enough for 2 car tires or 3 ebike tires. So I guess it is enough for 4 powerchair tires (90ml for a front tire and 120ml for a rear tire). Is it right? Is there any formula to calculate the amount of sealant for a tire?

[expresso]

i am sure it be fine - what ever you use - dont expect too much if using Tubes - i was worried myself first time i went to tubes on both my chairs - after i got used to it and stopped worring

i just add Air ever few weeks or so and thats it - but on one of my chair - the slime i added - i believe clogged up my air valve so - only on the front tires both of them - now i have a hard time adding air to them with my air pump - so i left them alone even at 9 PSI - its fine - not worried - next time i wont even add any slime to the front tires -

if using good Tires both front and rear - you be fine - its when the tires or trend is too low - is more of a concern for flats - i feel the tires i am using are so thick and strong - i dont worry about it now - but i dont run over anything that can give it a flat if i can help it - i guess i got over the fears of using tubes -

if you use it in the front - i would say dont over do it - it can clog the valves - if and when i replace the tubes or tires on the fronts - i wont add any to them in the future - only the rears i would add some

[snaker]

@expesso: do you remember how many ml sealant flux you put into each front and rear tire? As I understand, after adding sealant, you could inflate tires in a few weeks next. After that time, the sealant became curd, the valves were clogged and you could not inflate tires. The air in tires could not leak out neither. Is it right? Why wont you add sealant into the front tires? Is it because you cannot adjust their pressure after adding sealant?

[Burgerman]

If they clog, just temporarily remove valve core, poke a bit of wire in... No big deal.

[expresso]

@expesso: do you remember how many ml sealant flux you put into each front and rear tire? As I understand, after adding sealant, you could inflate tires in a few weeks next. After that time, the sealant became curd, the valves were clogged and you could not inflate tires. The air in tires could not leak out neither. Is it right? Why wont you add sealant into the front tires? Is it because you cannot adjust their pressure after adding sealant?

i dont know how much was added in the tires - since the bike shop did it for me - this was my first time going to tubes - i was worried and figured this cant hurt - not sure what went wrong with one chair - the other chair is fine - i can add air in both front and rear on one chair and the other one - just the fronts - have a problem with Air - so i left it alone - feels fine to me anyway

even if its a bit low - i may or may not replace the tubes - -- over some time i guess air did leak out - but for some reason - i cant use my air pump to inflate them again - i may need a strong pump - work fine on all the rest of the tires - just one chair - fronts only
but i still use the chair the way it is

[expresso]

If they clog, just temporarily remove valve core, poke a bit of wire in... No big deal.

i may try that during this winter - i will use the winter to get some extra cables done - and the tires - i will try the 300-4 size again with one chair i didnt test it on before - if it works there

then i can replace the tires and use those as spares for the other chair with the tires i cant inflat - or just replace them and then try to unclog them - not i am staying its the slime that may have got them clogged - i dont know for sure thats the issue - just seems most likely thats whats wrong - or bad tubes also - -

either way i will get extra tubes to have on hand - if the unclogging dosnt do it - i can just replace tubes and not add anything to them - i even have a heavy duty spare that were made for the airplanes -

i wont add any next time i dont think to the fronts - may be too problematic

[Burgerman]

Theres lots of types of sealant. Some has lots of fibres in it. That seals better. But can clog valves. But it takes just seconds to remove core, clean it with a cloth, poke a wire in the hole if blocked. And add air as you wish. I put about 1/4 tyre full...

[shirley_hkg]

Please advise rim width for 3.50-8 tubeless tyre ; 2.5'' , 2.75'' , 3.5'' .

[hobie1dog]

Please advise rim width for 3.50-8 tubeless tyre ; 2.5'' , 2.75'' , 3.5'' .

I would choose the 2.75

[Burgerman]

2.5, or 2.75 ok, 3 may be too wide and the rims which are 6mm thick (1/4, x2) mean that they may be wider or same width than the tyre. But you may get away with it as some tyres are wider than others!

[shirley_hkg]

@ ex-Gooserider : seller replied it comes with 2.75'' rim . Good pick too .

[ex-Gooserider]

That sounds great - send me a PM with details about how much for everything and how to get you the payment....

ex-Gooserider

[Furio]

@shirley_hkg. I too want a pair. please.

[shirley_hkg]

How would you like it , by sea or by air ?

[hobie1dog]

What is the O. D. Of the tire? 14 or 15 inches?

[Burgerman]

3.5 of tyre. + 8 of rim. + 3.5 of tyre on the other side. So 15.

[hobie1dog]

3.5 of tyre. + 8 of rim. + 3.5 of tyre on the other side. So 15.

Thanks John, but I think I need a 16 inch od tire to restore the balance of my chair after putting those tall 3.00-4 front tires on my S-636. Got suggestions on a 16" tire for a 3.5" rim?

[Burgerman]

Yes. But if you raise the height of your chair you will reduce stability in every direction. And the lateral direction, roll, (think airplane ailerons) will mean that you will lift weight off the casters intermittently and get caster shake problems.

The 110 80 tyres are about 6.92 inches plus 8 rim. So that gives you less than 15... At 14.92 inches.
The 120 70 tyres on my salsa are 5.67 inches plus 8 rim so that too is less than 15... At 14.67 inches.
Only the horid 4.00 x 8 will give you what you need. at 16 inches.

Of my 10 inch rims, with a 130 60 tyre. This give: 130mm x 70% = 91mm x2 (top and bottom) is 182mm, div by 25.4 to give inches, is: 7.16 inches of sidewall height, plus 10 inches of rim. So 17.16 inches... Total diameter.

download/file.php?id=4326&mode=view

[shirley_hkg]

Bigger but fatter also .

[shirley_hkg]

@ $34.00 US

[hobie1dog]

Looks like right at 15 inches( John was correct again), thanks for the pictures too.

[hobie1dog]

I thought that the 4.00-8 would have been taller than that

Now that I enlarged the image to see that it wasn't a 3.50 tire.

[Burgerman]

Working out imperial tyres is easy.
A 4.00 or 400 tyre is both 4 inches tall, and 4 inches wide.
A 3.50 or 350 tyre is 3.5 inches wide and 3.5 inches tall.

Its really that simple. So a 3.00 x 8 which is our stock tyre size is: 3+ 8 rim +3.
Since that 3 inch tyre is top and bottom. So 3.00 x 8 is 3+8+3 = 14 inches. Easy no?

Some tyres are marked differently. Like 4.10 x 3.00 x 4. Or. 410/300-4
These are the same thing. It means 4.1 inches wide, and 3.0 inches tall sidewall. So its the imperial way to describe low profile tyres. With sidewalls smaller than the width. So this tyre is, 3+4+3 = 10 diameter.

Metric tyres still use imperial rim sizes. So a 130/50 - 10 for eg means that its a 130mm wide, and the sidewall is 50% of that, so it is half of the 130mm. So that means you have to convert the 130 div by 2 = 65. And to convert to inches you divide by 25.4... Which happens to be 2.65 inches. So we know the tyre sidewall height is 2.55 top, 10 inch rim centre, and 2.55 bottom... Total wheel diameter is then 15.1 inches. Unfortunately, nobody makes a tyre that size!

But the above lets you work out the outer diameter of all tyre sizes.

[Burgerman]

Heres what the 3.5 wide rim looks like with a 120/70 tyre...

To calculate diameter you need to know 70% of the 120mm width. (120/70 is 70%).
That happens to be 120 x 70% = 88mm sidewall height. x2 since we have a top and a bottom... Is 176mm
176mm in inches is 6.92 inches. + the 8 inch rim, is 14.92 inches. Or 15 if you prefer.

[Burgerman]

Rear, ends up 27.5 wide.

[hobie1dog]

Just when I start comprehending things, then confusion sets in. In the pictures Shirley has, the bigger/fatter tires have 4.80/4.00-8 stamped on them. The picture with the tape measure show about 9 cm (3.5 inch) tall sidewall, or a 38-39cm od (15.35 inches). So wouldn't that make a 3.5+8+3.5=15 inch od tire? I'm just verifying computation as 38cm= 14.96" and 39cm = 15.35" as its hard to tell exactly what the reading is with the tape measure.

So Shirley, does this bigger 4.80/4.00-8 tire come on a 3.5 inch rim?

I noticed it has a load range C rating, wonder if the side walls are stiffer than a wedding night member?