Sideway movement of the rear wheel

I now see that my sketch was wrong :imp:

I thought washer 364 was centered on axle 340, but it is actually clamped between nut 373 and axle 340. So if you add a washer under the cup spring you need to add another washer 364 but of the same thickness to keep the same spring preload.

In my case, I want a higher preload, so I will not add an extra washer 364.

Calm down, most of us will not have realized that :smiley:
The drawing is still very good, I was quite unsure about this detail and therefore I wanted to disassemble a few bolts at the weekend.
Seems that we need in sum three washers to reach the target of a fully functional rear joint…

I’m also quite unsure how to proceed with this post because it will belong to several known issues of the rear Strida region. To merge the posts is not that good, I think…maybe pin this post and edit with links to the other posted problems…

Well the proposed solution is less simple than I thought: the distance ‘X’ is only 2mm. The cup spring thickness is 1.7mm, so it can only be compressed by another 0.3mm before being completely flat. It is not advised to push a cup spring until it is flat as the stresses in the spring become too high.

Adding a washer under the cup spring is therefore not advised, if the washer is about 2 mm thick (like the stainless steel one I found in a DIY shop), the cup spring will not be centered anymore and bolt 373 will not be screwed against axle 340.
Overtightening the bolt will damage the cup spring.
Adding a third washer between axle 340 and washer 364 is not ideal because it will not center perfectly and the inner edge of cup spring 367 will not be well guided.

On my bike, I replaced the soft steel washer 364 by a stainless steel one, which seems to be a much harder material. The original washer was quite deformed/worn out, and my first impression today is that the rear wheel swing movement has been reduced by almost 50% by bringing the preload of the cup spring almost back to its inital value.

Had no chance to examine more Evos, sorry for the delay :blush:
But I’ve found a good pic of a 3.0 Strida’s rear area- there is an additional washer below the cup spring!

For this pic I’d like to get the permission to use it from [size=150]florian[/size] - are you still here?
Please look at your mailbox…

Yes, perhaps not ideal…but if the thickness of the third washer is below that of the cup spring and the outer diameter very close to that of the axle it should work, I believe.
The third washer should fit inside of the cupspring; imaginable as some kind of axle elongation - shown in red color below.
(I’m here also thinking about a method for easy retrofit - a longer axle, like mentioned by Xentrax here, would be the better solution, but it would also need much more effort for exchange.)
Hope you don’t mind that I’ve used your image for illustration:

I agree with your ‘3 washers’ solution. However, for a retrofitting solution, the difficulty will be to find standard stainless steel washers with the proper dimensions (diameters and thickness).
You can of course order custom washers made by laser cutting or etching but it could be quite expensive, especially if you have to buy the raw material in large quantity :confused:

[i]This thread was “pinned” by the admin due to the importance of Bietrume’s discovery ten posts above.

Bietrume’s explanation does belong to several known Strida issues;

Belt twisted twice

Strida 5.0 “clicking” noise

Broken 373 Bolt

to name a few…[/i]

Here we have to be careful, several readers will not be able to verify what we are talking about:

Below are detailed screenshots of the exploded 5.0 drawings, this one from the owner manual 2008.pdf, identical to the drawing at this link:
http://www.strida.com/upload/Image/FAQ/exploded%20drawing%20strida%205.pdf

and that one’s from the nowadays on CD supplied Strida manual pdf or the link below:
http://www.strida.com/upload/Image/catalogue/STRIDA%20manual-0617%20revised.pdf

Well, the drawing was “enhanced”… :unamused:
(Just amazing that the recessed (!) snubber bolt 386 with its nut (!) 387 was not updated…)

For approval are here a few pics of a brandnew Strida EVO’s rear joint parts - exactly like the newer drawing - the cup spring (now 367-3) and the washer 364, there is no third “washer”.

Red arrow: Inner edge mark of the cup spring in the brushed aluminium surface of the frame.
Green arrow: Border of the silver paint, obviously was this area masked before the painting process.

The washer 364 is already deformed, outer edge marks of the cup spring are visible (red arrow).

Below, - sorry to use your pics without permission, florian - the rear area of a 3.0 Strida:

There ARE three washers!!

Could any 3.0 Strida owner please supply more info about dimensions and material of the “missing” washer 363?

My rear wheel developed some wiggle room last year. I took it out to ride last Saturday, after being stored since December, and the frame broke while riding. I’ve emailed photos to the admin to have them posted. I think the Strida is unreliable after being ridden for many years.

I purchased my Strida 5.0 in March 2008.

Hello ImpairedVisions,

I’m indeed sorry to hear that.
Broken frames are a very special issue I believe…
Would you mind to send me the pics too?
I’m quite unsure if Garry has enough time to post them…

From a production engineering point of view

A There seems to be a tolerance stack buildup due to:
Torque on how axle is screwed into rear forged joint
Thickness of rear forged joint
Surface texture of rear forged joint
Finishing of of rear forged joint
Thickness and wear of Large dia Nylon washer
Thickness of Bottom tube (and its nylon insert/end cap)
Surface texture of Bottom tube
Finishing of of Bottom tube
Axle length tolerance
Spring washer biting into rear tube … or … Thickness and wear of any thin washer under Spring washer
Spring washer, thickness’
Spring washer Hardness
Spring washer edge sharpness
Spring washer surface finish
Spring washer consistency - (taiwan supplier ??)
Lubrication (clear grease).
Small washer Thickness/quality/surface finish
M8 Bolt torque & Thread lock condition.

B The part(s) that takes up all this tolerance stack buildup, and keeps the best combination of folding stiffness vs Joint stiffness/no play is the [b]spring washer/b. This/These should fit between the bottom tube and the ‘small washer’.
The small washer should be torqued up and ‘locked solid’ by the M8 Bolt, on the end of the axle. Such that the Bottom tube rotates.

The spring washer should rotate with the bottom tube (as its larger diameter, left sloping, bottom end of the cone has more friction than the smaller diameter ‘top end of the cone’ … which in turn runs against the harder, more wear resistant (and lubricated) underside of the small washer…

See Strida 1 manual for a good description (without the small washer but with an M8 Button head screw) >
issuu.com/mark77a/docs/strida1-owners-manual/19
issuu.com/mark77a/docs/strida1-owners-manual/45

Dear Sir,

thanks for your message - after a long while; I’m happy that you’re still here :smiley:

Teaching us is very nice indeed, just we did already know several of the mentioned facts and of course we’ve read all informations available.
But it seems that Ming cycle didn’t read it…

Good to know how it should be, but in reality (at least on Strida EVO and 5.0) is the small washer definitely softer than the cup spring.

I’ve been reading this thread with interest.

I have a Strida SX bought from Velorution, London UK in 2013. It’s been my daily commuting bike (5km, so not far). I started experiencing problems with the belt about a year ago - twisting there times. Velorution replaced the belts and then recently the flywheel and the belt, because they were worn. But now the bike appear to have sideways movement in the rear wheel as quoted in this thread - enough that it caused me to stop the bike whilst riding, fearing that the rear wheel had worked loose. In examining the rear washer (364) inside the bolt, it appears totally deformed. I don’t know the state of the cup-spring (367-3) because I have always left the repairs to Velorution as they are authorised Strida mechanics. I will try and post photos now. Has anyone come up with a fix for this yet? I’ve asked Velorution to order new 364 & 367-3 parts to see if I can at least get back to square one.

I’m 1.89m tall and 87kg so put a fair amount of power through the bike, but not close to the 100kg maximum. I expect mechanical parts to wear. I’ve actually upgraded to the Strida alloy chain set because the flexing in the plastic one worried me, but I had belt issues before this upgrade.

Any thoughts welcome.

Alistair :smiley:

Hi Alistair,

quick digression before: Authorised doesn’t mandatory mean knowledgeable…
(Not for the first time.)

Yes, there are two fixes existent for that,
one is here, but please note especially the last post.

Do you know a trustworthy mechanic who is able to unmount 373, 364, 367 and examine the bottom tube hole?

Thanks BSA,

Every time I have taken the bike into Velorution, I get “Oh we’ve never seen that before” which doesn’t fill me with confidence. It looks like a simple fix though…if as you say the bottom hole has not become oval.

I’m not optimistic, being two years old that it won’t be oval. I’ll have a look this weekend. Whats the solution then - drill out the hole and fit a sleeve on the axle? Or a new bottom tube?

Alistair.

Hi Alistair,

thank you for the feedback :smiley:
Yes; there are still companies which are interested to sell - but not support :confused:

Hmmm…hard to tell; it will be oval; but how much?
If it is much deformed will be a new tube the easier way, they are not that expensive as one might think (accidentally depending on distributor).

I believe the bottom tube, once worn, could be saved just one way:
Replacing of part 100-07 (plastic tube insert) by Aluminium, equipped with needle bearing.
One, two securing bolts of the perhaps also elongated insert across the tube in 90° alignment to the axle. Creating of a fine adjustable pretension mechanism (= friction between bottom and seat tube) would complete a durable rear joint.

Maybe you want to help me forcing Ming for realization? :smiling_imp:

Perhaps you’re just too pessimistic and the tube hole is fine.

Chris

Took off the rear bolt to assess the state of the cup-spring and washer, plus the damage to the bottom part of the frame from the cup-spring.

Washer is totally deformed - you can clearly see the shape of the bolt imprinted into it.

Sideways view shows the deformation further:

Cup-spring has eaten into the frame:

I didn’t want to take the bike apart further, so hard to judge how ovalised the bottom hole might be. Both your fix Chris, and the Canadian option which Bill emailed me about seem like the way to go. Can I order one of your kits Chris please? Thanks Alistair

Uargh… :open_mouth: this frame is looking awful :confused:

I’m really in doubt if my usual shims are suitable for that deep grooves,
might be better to try thicker ones…wtf…
However…of course you may try - please pm me - thanks.

Looks like this bike was much more often folded than ridden…

Edit:
But once disassembled it’s clear why the cup spring can’t generate much tension, no?

It’s folded and unfolded four times a day! The freewheel and belt are new. So I guess it appears that way. I will PM you. Alistair

Hello Alistair,

your kit was shipped already at Monday, so it should arrive soon :smiley:
Good luck!

The kit arrived yesterday - great instructions and impeccably packaged up, so thank-you very much.
Fitted it today, and the sideways movement of the rear wheel has gone completely. I’ll keep you posted to how it fairs over time, but hopefully this is a great fix for the cheap components supplied with the bike. I’m convinced that the belt twisting problems all stem from the movement of the rear wheel… which in turn comes from one cheap washer. :unamused: :unamused: :unamused:

The thin washer seemed to cover the damage to the frame well:

Thanks so much for your help and generosity Christian - especially since as you explained, you have no official links to Strida other than being a fellow rider.

In contrast I have yet to even be called back by Velorution, where I bought the bike, and asked 10 days ago about ordering the replacement existing washer and cup-spring. Pretty poor customer service.

Best regards
Alistair :smiley: :smiley:

Hello Alistair,

I have to say thanks to you for being my test pilot :smiley:
Looking forward for your experience…

Best wishes,

Chris