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Dnepr sidecar spindle diameter & wheel fit


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#1 MotoJ

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Posted 16 September 2013 - 09:19 AM

Hi all,

Sorry for this long post!

I've been having problems with my sidecar wheel loosening up every few weeks. It develops a wobble, I re-tighten, and it's good, then gets wobbly again down the road.

I have a 60s-70s era Dnepr sidecar, no drive, no lug for sidecar brake. It came without a wheel. I fit a Dnepr wheel with a sidecar brake backing plate, but with the brake apparatus and shoes removed. I think it probably should have been a plain sheet metal backing plate, like for a K750, but I couldn't find one, and I didn't think it mattered.

In any case, upon closer inspection this weekend, I noticed that the bearings seem loose on the spindle. The spindle measures approx 19.5 mm, and the ID of the bearings is about 20.1 mm. The spindle diam. measures differently along its length- poor machining, I guess. Anyway, that seems like a lot of slop. I can feel it rocking the wheel by hand. I tried a Ural wheel and also a spare set of Timken bearings- same slop.

Is this normal for Dneprs, or do I have a bad spindle? How can I tighten up my wheel and get rid of the wobble? BTW, with the backing plate I am unable to fit a washer under the castle nut I have. Should it have a washer? Is there supposed to be a spacer between backing plate and wheel, or between swingarm and backing plate? There is none, and I noticed aluminum dust in the wheel, where they are grinding together.

Those of you with Dpepr cars- how snug is your sidecar wheel on the spindle? Do you have the same slop I'm describing?

Your sage advice is welcome, as always!
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#2 dneprlover

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Posted 16 September 2013 - 09:46 AM

Something is wrong somewhere . The spindle should be 20mm diameter ( they sometimes snap and can easily be replaced) some of the east european sellers sell them.

There should be a thick washer between the backplate and the wheel bearing spacer on the drive side of the wheel. This allows the spindle nut to tighten on the wheel bearings and not on the backplate. when the wheel is slid on the spindle, it is followed by either a washer and bearing cover or a combined one, then the wheel nut. A split pin prevents this from moving and altering tightness.

Are you just tightening the spindle nut to solve the problem or are you adjusting the bearings with the 'c' and 'pin' spanners?

I have had several people come to me with continuous adjustment problems and it is usually either knackered wheel bearings or they have been incorrectly installed in the wheel.

Personally, I think your spindle would be ok if you added a thick washer after the backplate, please strip, clean and reassemble the wheel bearings first though ( standard 30204 bearings in all wheels if you want to replace them)

Edit. I've just measured 2 spare swinging arms, the spindles stick out exactly 5-1/2" on both. What is your measurement. I run a bike with the same set up as yours and can soon strip the wheel off and see how it's set up. Would have to email pics if you wanted them though as I can't do that with the tablet I'm using

#3 MotoJ

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Posted 16 September 2013 - 10:52 AM

Thanks for the reply- that's a lot of good info. I am indeed missing the spacer twixt backing plate and wheel. I suspected one was supposed to be there, but hadn't found a diagram to know for sure.

I also think the castle nut I'm using is too deep- ones I've since seen in photos during my research are much thinner. That's keeping me from fitting a washer and the spacer on the spindle. As it is, I can just barely get the nut on enough threads to fit the cotter pin. Forget about a bearing cover. I guess I'll grind the backside of the nut down some.

I did snug up the bearings, but the looseness isn't in and out, it's looseness between OD and ID, spindle vs bearings. For all I know some farmer hand-turned the spindle himself, rather than finding a Dnepr manufactured spindle. the car was in rough shape when I got it- I found a piece of 1970s Avocado color refrigerator panel welded in as a floor patch!

If you have pics of the order of assembly of your wheel, that would be very much appreciated!
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#4 dneprlover

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Posted 16 September 2013 - 11:04 AM

Standard castle nut is 1/2" long with the cutouts for the split pin being 1/4" deep. Washer either side of wheel on spindle is 30mm od x 20.5mm id x2 mm thick.

Does that help? If you know anyone with a lathe, they could turn the nut down in length for you

#5 MotoJ

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Posted 16 September 2013 - 11:24 AM

That's perfect! I think my nut is more like 7/8". I bought it at a hardware wholesalers.
I do know a lathe-owner. He's like nailing Jello to a tree, so I may end up grinding.

Thanks for your help!
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#6 dneprlover

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Posted 16 September 2013 - 11:32 AM

Spindle and nut available on ebay from my preferred supplier item number 141058965518.  You ideally need use of some heat and a hydraulic press to change one but I have used a brick wall and a car jack before now

#7 racepres

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Posted 16 September 2013 - 11:39 AM

Forgive me if you already have this worked out..But, It is important that the bearings have an inner "spacer" to tighten against.
The nut should be able to go very tight indeed without binding the bearings, as the spacer won't allow the bearings to be over-tight.
RP

#8 dneprlover

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Posted 16 September 2013 - 12:24 PM

No inner bearing spacer on a Dnepr?  Quite easy to diagnose as the bearings fall out of their outers and the wheel can be rocked at least 4" each way side to side. 1/8" either way on the length of the spacer won't matter as the bearings can be adjusted to compensate. Tightness of the spindle nut has no relationship to the load on the bearings

#9 Pete Swede

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Posted 13 October 2013 - 06:13 AM

I didn't see this thread until now... I had pretty much exactly the same problem with Nikita (M72 1953). My sidecar wheel got lose and wobbling and when I took the wheel of I saw that it's been eating away metal on the backplate (big dustcover plate?). My castle nut was to thick and it was almost impossible to get the split pin (cotter pin?) in, had to use a really thin one. Did not have any room for washer or dust cover (small one).

When I changed my wheels from "bottle cap" to "tin cans" the problem solved itself and I could get the castle nut there with washer and dustcover and the wheel stopped to eat in to the big dustcover back plate.

I got the same kind of difference after the wheel change (but kind of reversed) on my front and back wheel where I can't tighten the nuts to much now since that locks the wheels completely.

I asked about that in an earlier thread an I got the answer that I had wrong (to short) distances (spacers?) in the wheels now.

Posted Image

http://www.russianir...&hl=spacers  

Anyhow, I had exactly the same problem as you, and when I changed wheel type it disappeared... So maybe your spacer is to long now, like my was before. Don't really know what kind of Dnepr wheel you have on...



What concerns me now is that I cant have a mix of long and short spacers on my bike since I want to be able to change my wheels around... I imagine that if I put the 21mm spacers on all the wheels I will be back having the same problem with my sidecar wheel again... :wacko:



Could it be different lengths of the sidecar wheel axles depending on type of wheels???...  :huh2:




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