Marathon Racer tyres and LT plastic rims

Strida Forum Strida Problems and Answers
1

To replace the original Kenda Kwest equiping my LT, I purchased 16" Schwalbe Marathon Racer tires and Schwalbe inner tubes. I wanted faster tires combined with a good puncture protection : the Racer has the HD speed guard, which is a densely woven protection belt.

While there is no easier bike than a Strida to get tires on because of its single sided supported wheels, it took me more than one hour to get the Marathon Racers properly fitted. :imp:

I could not get the tires centered on the rim because there was always a small portion (1/8th of the circumference) of the tire bead which would not fit in the bead seat of the rim. Applying soap on the tire beads did not help.
I finally succeded by inflating the tires to 6 bar with a compressor rather than with a hand pump, the quicker inflation of the tire helping to set it properly.

But this morning, for my first trip with the Marathon Racers, I managed to have a puncture after 3 km :imp: . I might have pinched the inner tube when I mounted the tire :question:

I just repaired the tire at the office but did not manage to put get the tire properly centered. I will have to ride back on a jumpy Strida :angry:

Did some of you experience the same issue? Is it due to the LT rim design?

2

Just tried to mount an 1,5" Marathon Racer onto an LT rear wheel - no way, exactly the same problem.
I didn’t use talkum powder, pressure was above 7 bar.

Gladly I’ll tell you my meaning, but at the same time I’m sorry for not being able to explain it properly.

The LT rims and the 16" spoked rims simply do not match to wide tyres, I think these rims are built for tyres with 1,25" to 1,5".
So, 1,5" inch is the upper border, depending on the tyre a 1,5" wide type might fit - or not.

I mean the Kenda 1,5" tyres are a little bit bigger (inner diameter) than Schwalbe Marathon Racer, maybe they are also more soft.
The inner distance from flange to flange is similar at both rims (spoked 20,2 and LT 20,4 mm),
but the beads of the usual spoked rims and the LT rims are different, beads of LT are bigger.
A little bit here and another little bit there might together cause the mentioned issues.

Also, it is impossible to mount wide tyres (~1,9 inch) on the spoked 16" Strida wheels…
I really don’t know why, but it seems that the tyre width is somehow connected to the rim width - for example it is no problem to mount the Maxxis Hookworm (1,95") on an Alex Y303 rim…these rims have an inner width of nearby 24 mm.

According to my bike dealer (and to several reports at different bike forums) will be the only chance to pop these tyres out of the rim the use of talkum powder and overinflating. Tyres and tubes should be able to withstand up to around 10 bar, of course I’m unsure whether the LT rims will manage that pressure (from my feeling I’d say yes - because you actually will not ride with such a high pressure).

I guess you will know the following; it is meant for readers with less experience in tube/tyre repairs:

First should one edge of the tyre be pulled over the rim, then the tube pushed into the tyre and at last the second edge of the tyre be mounted on the rim.
While pushing the tube into the tyre it should NOT be completely empty - a little bit of pressure will avoid the creating of wrinkles.

Source: http://sheldonbrown.com/flats.html#tirerepair

3

Ok, went for some talcum (“c” is correct for English, btw) powder to the next drugstore (50 grams for 50 cent) and tried again by using 9,0 bar…

At first sight it was looking good, the tyre crawled out of the rim, but not the whole thing
Such a


Maybe it does by applying 12 or more bar, but neither my pump nor me wanted to figure that out…
Anyway, dont try that in your appartment, this white powder will be everywhere after such an action!

Did you ever think about switching to 18 inch or building your own 16" wheels?

4

Hi BSA,

I’m glad to see that there is a fundamental compatibility issue here, but I’m not really convinced by the explanation about the width. According to Schwalbe, tires of up to 62mm width should fit, considering it is a 19mm (20mm is not standard) width rim.

I would say that the issue here is the tire bead diameter which is smaller than the rim bead seat diameter: could you please measure this on your rims according to the Sheldon Brown method (http://sheldonbrown.com/rim-sizing.html)?
Here is what Schwalbe says:

And on 16" wheels,this 9.4 mm tolerance has more effect than on a 28" wheels.

The problem is that there are not many tire alternatives to the Marathon Racer for 16" wheels: the Innova tire proposed by Vanmoof is just a copy of the Marathon Racer with potentially the sames issue, and it is almost twice the price of a Marathon Racer (I paid less than 15€ per tire) :imp:

I don’t want to go for 18" wheels because I am happy with the current gear ratio. Bigger wheels will make climbing more difficult. I don’t want to invest in spoke wheels either, I have put enough money in this small bike :laughing:

I know indeed how to mount a tire to avoid inner tube pinching, but I repeated the operation several times and tried to center the tire with the tire levers as well, this with a very negative mindset :imp: … a puncture was the result :cry:

5

This is the solution proposed by Schwalbe:

Well that’s what I did already, I still have to try with a higher pressure than 6 bar.
8 bar is the maximum I can get out of my compressor and I don’t want to go much higher.

6

I can say that I have the same issue with my Strida 3. I use to try several times until I get a “not so bad” result.

On the other hand this problem was also posted on bikeforums.net

And I’m not sure if my old plastic rim is able to handle those high pressures… :mrgreen:

7

See page 3:

strida.com/upload/Image/cata … 20Mark.pdf

8

Thank you Carlos71,
interesting to know that the older 12-spoke plastic wheels are obviously of the same size as the newer 5 spoked.

I’ve also tried to mount Schwalbe Big Apple (2" width) onto LT wheels - with the same result like the Marathon Racers.

The measuring of the wheel and bead diameters of LT, original 16" and Alex Y 303 rims was surprising:
I could not find a significant difference…
Honestly, I do not understand why Sheldon mentioned the “lower” bead seat diameter, I mean the “upper” one is crucial?

365Ă—611 27.5 KB

LT rim
Outer diameter: ~ 318,5 mm
LBSD: ~ 305,5 mm
UBSD: ~ 311,5 mm

16" rim
Outer diameter: ~ 318,0 mm
LBSD: ~ 305,0 mm
UBSD: ~ 314,0 mm

Y303 rim
Outer diameter: ~ 319,0 mm
LBSD: ~ 305,0 mm
UBSD: ~ 314,0 mm

Instead of Sheldon Brown’s measuring method I’ve used a marking gauge and a steel ruler.

9

Well it is not Sheldon Brown’s fault: this diameter is defined in the ETRTO standards. You probably noticed that the lower bead seat diameter is 305, which is also the size of the tire.

So the only explanation I have, is that the tire bead seat (=the groove) where the tire bead fits is narrower on the plastic rims than on the steel ones: 311,5-305,5=6/2=3 mm vs. 314-305=9/2=4.5 mm.

10

I just wanted to post that I just purchased and mounted 2 Schwable Marathon Racer 16 x 1.5 tires (40-305) and I also had the same trouble with them not mounting properly exactly as the picture shows. I have the aluminum rim/plastic spoke wheels just like in the picture as well. I was finally able to get the tires to mount properly by soaping the rims and tires with soapy water and inflating to 120psi. It took about 3 mins for the tires to slowly push out to the edges of the rim but they did. When I fully deflated the tire it popped back off the rim and required the same high pressure to remount. The second time I deflated the tire to around 40 psi it remained properly mounted, and then brought the pressure up to the max level 85. The second tire was much easier once I knew who to make it work. Nice ride on these tires! Mark