Advice required on a brompton conversion

[jerrysimon]

Disappointing but easy to get it unlaced and rebuilt into a 349mm rim. The only problem at the moment is that the 36h Sun CR18 rims (Bromptons rims are only 28h) are not currently available and are on back order with SJS

http://www.sjscycles.co.uk/sun-cr18-16-x-1-3-8-(349)-abt-alloy-rim-silver-36-hole-prod8542/

Personally I prefer the Brompton rims for ease of getting tyres on and off. The CR18 whilst better built and stronger have a very narrow well. I mangaged to get some stock blank Brompton rims redrilled with 36h. Wish I had got a few more done now.

As with all Chinese sales, communication is often lost and you have to be very specific about what you want.

These set backs are common but usually there is always a way round them just takes a little time and patience. You will really appreciate it though when its finally done and you go out for your first test ride.

Regards

Jerry

 

[catsnapper]

Well the kit was delivered but the supplied wheel is way too small for my Brompton. It has a 317mm/12.5" diameter rather than the 349mm/13.75" diameter.
Slippa

The obvious answer is to have a wheel built with the motor and correct size of rim, you'll have a better quality wheel and less problems for the extra cost.

The only potential problem with this route depends on how many spokes the hub/wheel uses. The current main supplier of 36h Brompton size rims Sun Ringle, appears to have discontinued manufacturing them.
They're still available with 28h and 32h, and obviously 28h Brompton rims are always available, but it is possible to lace a 36h hub into both 32h and 28h rims. The same situation has arisen with another Brompton convertee on the forum - his only answer is going to be a 32h rim with a 36h hub.

I'm currently looking at any potential problems with lacing motor hubs into 28h rims as these are likely to be the easiest to obtain in future.
Obviously there's no problem with a conventional hub, but I'm hoping that with the correct type of spokes and and a carefully built wheel, there won't be a problem with most motors.

Alan

 

[jerrysimon]

Tongxin seem to manufacture hub motors in a 28h configuration now. Not much help in your case but worth noting if others are thinking of getting motors for their Bromptons.

Alan, I have seen it done and I will certainly be interested to see you solution

What a shame they have discontinued the CR18 36h rims.

Regards

Jerry

 

[slippa]

Thanks Jerry - I appreciate the encouragement.

I've just nipped to the local bike shop to enquire about some rims. He stocks the brompton rims but they are of course drilled for 28 holes rather then 36. He has reached out to one of his contacts who might be able to help and he says he'll get back to me in the next day or so.

How/where did you get your brompton rims redrilled? Wouldn't that leave them weaker with so many holes? My calculations have the origin holes about 36mm apart for the 28 holes and 28mm apart for the 36mm. That's only every 7th hole from the original drilling that can be re-used becoming every 9th spoke in the 36 spoke configuration.

I suppose the other problem is calculating the correct spoke length and getting them made.

It is times like these that I regret taking the DIY path.

Cheers
Matt

 

[slippa]

Thanks Alan.

I'd appreciate any advice/options you can provide.

 

[jerrysimon]

Matt the rims where blank/undrilled to start with and then drilled with 36h

Last time I checked with the guy that did them for me he had none left

Alan (as posted above) is the man to cut you a spoke or two

Regards

Jerry

 

[catsnapper]

Hi Matt,

Making 'mismatched' wheels can be done with different lacing patterns, depending on hub and rim size, but all require several different spoke lengths, patience and a clear head
Using a 28h rim needs more of all those than a 32h!

Alan

 

[catsnapper]

If anyone wonders what a 36h hub in a 32h Brompton size rim looks like, it looks like this - not much different from a normal wheel



Alan

 

[jerrysimon]

Nice job Alan

Regards

Jerry

 

[sergiu71]

Hi guys. I'm Spanish ebike kit store owner Ruedas Electricas - Kits de conversion bicicletas electricas plegables y de montaña - Baterias. I ordereded 20 pcs of 349mm rims with 36h. Next week I will receive it. I still dont know what will be the price and shipping costs but you can drop me a message.

Regards

Sergio

 

[sergiu71]

Hi guys. I'm Spanish ebike kit store owner Ruedas Electricas - Kits de conversion bicicletas electricas plegables y de montaña - Baterias. I ordereded 20 pcs of 349mm rims with 36h. Next week I will receive it. I still dont know what will be the price and shipping costs but you can drop me a message.

Regards

Sergio

 

[shemozzle999]

Hi slippa,

349mm rims with 36h on ebay:

Pair of 16 x1 3/8" (349mm) 36H silver alloy wheel rims | eBay

 

[shemozzle999]

Hi slippa,

349mm rims with 36h on ebay:

Pair of 16 x1 3/8" (349mm) 36H silver alloy wheel rims | eBay

Please ignore this post as the listing on the Canadian Ebay site appears dead - it is a UK supplier and I have sent a message to see if he still has any stock - I will report back if I receive a reply.

Update: I have received a reply - unfortunately they are no longer in stock.

Dear shemozzle999,
Sorry! These items now out of stock.
David- 1003david1003

 

[jerrysimon]

I can see someone cashing in on these. Supply and demand

I have also contacted someone I know who had blank ones that he drilled for 36h.

Regards

Jerry

 

[shemozzle999]

I can see someone cashing in on these. Supply and demand

I have also contacted someone I know who had blank ones that he drilled for 36h.

Regards

Jerry

I think I will bookmark him anyway as he seems to specialize in small wheel bike spares.

Quote from his ebay shop:

"Consumables for small-wheeled bicycles. Supporting the preservers and riders of Moulton machines. Inner-tubes for 14"/16"/17"/20" wheels. Tyres, sprockets, cables, spokes, tools, accessories, used spares. Lightning dispatch around the world. Friendly & enthusiastic service to the eBay community"

 

[slippa]

Thanks shemozzle999, I actually spotted these on Thursday and contacted him immediately. He doesn't have any left in stock and recommended I try St John Street Cycles or Avon Vally Cyclery.

 

[jerrysimon]

See Alan's comment SJC don't have any and it appears they are being discontinued.


shemozzle999 yes he is worth keeping in contact with.


Regards

Jerry

 

[catsnapper]

The last of the CR18 36h stock will supposedly be with SJS later this month, I don't know how many, or exact date.
Sun also make a CR 14 rim in the same size(349) with 36h. A colleague in America stocks them, but they're slightly narrower, don't appear to be stocked in Europe, and I've no idea if they are current manufacture.

As it's getting an increasingly critical problem, I'm looking to see if I can supply the excellent, but slightly expensive Australian/American Velocity rims at a realistic price. They are made in the 349 (305 is discontinued) size in a variety of drillings including 36h.
Velocity rims have an exceptional reputation for durability as well as looking good, so I'm hoping this will prove a superior alternative to the CR18 rims.

I know I could find relatively cheap Chinese rims, but I've seen way too many with poor quality thin walls where the spokes pull through in no time - in all sizes, including 349
I AM aware there are some decent Chinese rims out there, not everyone has problems, but right now I'm not gambling on finding them.

Just to balance things up, there are some European rims with a reputation for being thin walled and brittle, resulting in a rather short life expectency

End of Saturday afternoon muttering...

 

[shemozzle999]

Seeing if these people could do a 36H silver version:

eBay - The UK's Online Marketplace

 

[shemozzle999]

Seeing if these people could do a 36H silver version:

eBay - The UK's Online Marketplace

Sorry no joy here either - they can not supply 36H - but I did find a video of how rims are made - warning, turn the sound down.

Production on Vimeo