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Post by webrest on Oct 1, 2012 0:50:14 GMT
Hi All,
I need help and knowledge from the community.
First Up My VBB is a Viet import so let's get that out of the way first.
I know already all the horror stories and I could care less.
I am happy with mine.
So with that out of the way.
Having been delivered with 10" wheels at my request I now find that perhaps I should have put more thought into gearing than I did.
Racing Formula Fords for years you would think that I would have payed more attention to gearing after changing gear ratios all the time in the Hewland boxes for the different circuits.
My thinking was bigger wheels less revs, higher top end. Having asked for the 3 port configuration I figured somewhere along the line all would balance out.
What I underestimated was just how low powered a Vespa 150 is.
My bad.
It's OK and I can easily tolerate the shortfalls it will climb in 3rd gear in the Yarra Ranges where I live.
BUT I'm a fiddler.
What do the knowledgeable consider is the best all round gear option for an 8" wheel VBB converted to a 10" ?
I have counted all the gears, done the maths and they do appear to be standard issue for a VBB-VBC 8" scooter. At least from the specs I can find.They are not all that easy to search for the different models in one spot on the web.
My ratios are as follows:- Primary 67/[22 Had to assume,couldn't see to count teeth] 3.045
Ist 57/13 13.35
2nd 52/17 9.32
3rd 48/22 6.64
4th 42 27 4.73
Is it just a matter of changing the primary gears and keeping the gear set that's already existing or do you have to change out the the primaries and the main gear set?
My thinking is changing the primaries will do the job but hey, what do I know I have already proved I have a lot to learn about my new Vespa hobby.
I will learn though one way or another I'm becoming real fond of these things.
Looking forward to any advice
Dave
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Post by kru251 on Oct 1, 2012 16:12:44 GMT
Hi All,
I need help and knowledge from the community.
"First Up My VBB is a Viet import so let's get that out of the way first.
I know already all the horror stories and I could care less".
I think you mean you COULDN'T care less (about others opinions).
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Post by sbwnik on Oct 1, 2012 16:54:51 GMT
You're a bit knackered TBH.
You've a gutless motor that's over geared with 10" wheels.
They fitted 8" for a reason - the motor would pull the gearing that way. The two port motor is terrible, and although you could chase up a bigger cylinder for it (I think Polini do one), but it'll still struggle.
From here you've two choices: Either source a P range engine which runs 10" wheels as standard, or go back to 8" wheels, which will not only solve the immediate problem, but will improve the braking and the styling. It'll just be slow though...
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Post by bryno on Oct 1, 2012 19:53:58 GMT
Some stuff on here which may help you inc a gear ratio calculator www.scooterhelp.com/tuning/vespa.gearing.htmlHard to work out how it will be with a different set up given the power output of your 2/3 port is not know, but my logic would be that a 3 port 150 will be similar to a PX125 output, so i'd go with sticking in the entire box from a PX 125/150... All guess work though! |
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Post by webrest on Oct 3, 2012 14:39:20 GMT
Hi All,
Thanks for the input. and info.
It looks as though there is no clear or trodden path to answer to this question by gearing alternatives but returning to the 8" wheel seems to be be a reasonable solution. It is either put up with the current configuration, which really isn't too tragic anyway or take it back to standard and be done with it.
The 8" inch solution however brings up 2 further questions.
1/ Are the splines the same on both the 8" and 10" wheels?
2/ I believe the front fork has been replaced to accomodate 10" wheel. would it be acceptable to run the 8" wheel on it or would the fork have to be also changed back.?
Thanks again
Dave
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Post by webrest on Oct 3, 2012 14:53:13 GMT
Hi All, I need help and knowledge from the community. "First Up My VBB is a Viet import so let's get that out of the way first. I know already all the horror stories and I could care less". I think you mean you COULDN'T care less (about others opinions). I do care about the opinions of others otherwise I wouldn't be on the site seeking help from those that have been around scooters far longer than myself. I made my decision where to purchase with my eyes fully open being prepared for what may come. And yes I made a wrong decision with the wheel diameters. All I was alluding to was that I didn't want the topic to turn into another Asian scooter bashing thread. |
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Post by bryno on Oct 3, 2012 16:31:03 GMT
Yes the hub splines are the same AFAIK, but the key difference between 10" & 8" is the brake pins.
On an 8" engine there is one pivot for the brake shoes, on the 10" there are 2, that means that 8" & 10" hubs are not interchangable as the brake shoes don't match.
What you need to establish is how they managed to convert it to 10" hubs, be a case of whipping off the rear hub and take a look at the brakes, maybe they welded in new brake pins.. I am interested to know, usually people do this the other way round, i.e take a modern PX engine and convert to 8", which is a well trodden path.
If you do now have '2 pin' brakes, the only way I know to convert back is to use a Vespa Super rear hub and split rim, which is 8" overall, but uses the same brake shoes as a 10" wheeled scooter so can work with a 10" hub.. confused yet? I am!
Only problem with this set up is your front and rear hubs will look different, unless you also source Vespa Super front hub and rim set up as well.
Re the front, it depends how they did the conversion, there are a couple of ways of doing it, post a pic of the fork side of the wheel and we can work it out..
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Post by kru251 on Oct 3, 2012 19:20:24 GMT
Hi All, I need help and knowledge from the community. "First Up My VBB is a Viet import so let's get that out of the way first. I know already all the horror stories and I could care less". I think you mean you COULDN'T care less (about others opinions). I do care about the opinions of others otherwise I wouldn't be on the site seeking help from those that have been around scooters far longer than myself. I made my decision where to purchase with my eyes fully open being prepared for what may come. And yes I made a wrong decision with the wheel diameters. All I was alluding to was that I didn't want the topic to turn into another Asian scooter bashing thread. Well I couldn't care less about others opinions (that's why I like 'MOD' and have various Tiger tails on my scoots  ) but I do care about good advice and engineering practices which is why I'm on the site! Sound like yours is not a simple job to convert to get good gear ratios, but I wish you luck and will follow the thread. Keep us informed of the results eh? Cheers, Chris (ex Brands Hatch, Lydden, Castle Coombe, Silverstone and Thruxton race marshal; love FF's!!!) |
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Post by sbwnik on Oct 3, 2012 23:34:49 GMT
Bryn, I chucked 10" wheels onto a Super engine years ago just by changing the backplate and hub, although it was a late version of the engine.
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Post by bryno on Oct 4, 2012 7:58:36 GMT
Yes, its easy on the Super as it has the 2 pin brakes, all the other 8" wheeled engines like the VBB have the silly single pin ones and the smaller hub which isnt compatible with the 10" hub.. so its a right faff to convert!.
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Post by webrest on Oct 5, 2012 15:08:31 GMT
Bryno
"If you do now have '2 pin' brakes, the only way I know to convert back is to use a Vespa Super rear hub and split rim, which is 8" overall, but uses the same brake shoes as a 10" wheeled scooter so can work with a 10".."
Bryno, I don't understand what you mean by single pin and 2 pin.
Can you pls. explain to me?
Dave
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Post by webrest on Oct 5, 2012 15:23:34 GMT
I do care about the opinions of others otherwise I wouldn't be on the site seeking help from those that have been around scooters far longer than myself. I made my decision where to purchase with my eyes fully open being prepared for what may come. And yes I made a wrong decision with the wheel diameters. All I was alluding to was that I didn't want the topic to turn into another Asian scooter bashing thread. Well I couldn't care less about others opinions (that's why I like 'MOD' and have various Tiger tails on my scoots ) but I do care about good advice and engineering practices which is why I'm on the site! Sound like yours is not a simple job to convert to get good gear ratios, but I wish you luck and will follow the thread. Keep us informed of the results eh? Cheers, Chris (ex Brands Hatch, Lydden, Castle Coombe, Silverstone and Thruxton race marshal; love FF's!!!) Yeah I really loved my time in FF's very competitive even in Historics. Lot of the drivers down here in Australia are all old hot shoes from the day and they take no prisoners when competing. First corners can be carnage They still compete like an Australian national title was at stake. From what I can see Britain is the same. The Americans on the other hand from what I viewed are extremely mild mannered. No passing in corners, wheels in the dirt etc. Ah! don't get me started I not on this forum to rabbit on about FF's |
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Post by kru251 on Oct 5, 2012 20:34:43 GMT
Excuse the distraction Vespa lads and lasses! I always thought FF starts were like a pond when you disturbed the surface and all those 'waterboatmen' insects with the spindly legs were going left/right/anywhere. 
Rather like this at my last meeting from Brands:-
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Post by bryno on Oct 5, 2012 21:05:23 GMT
Bryno "If you do now have '2 pin' brakes, the only way I know to convert back is to use a Vespa Super rear hub and split rim, which is 8" overall, but uses the same brake shoes as a 10" wheeled scooter so can work with a 10".." Bryno, I don't understand what you mean by single pin and 2 pin. Can you pls. explain to me? Dave Pop the rear hub off and you have 2 brake shoes, they attach to either a single pivot pin, or 2 pins, one for each shoe. The 2 pin set up makes the overall diameter of the brake shoes larger so it matches the hub you'll find on a 10" wheeled Vespa (or an 8" wheeled Vespa Super), your VBB will have originally had the smaller diameter single pin brakes which only fit inside the VBB style hub.. if you can get the hub off and take a pic we can work out exactly haw the conversion was done. |
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Post by webrest on Oct 6, 2012 13:29:42 GMT
Ok. I get what you mean with the pins. I am attaching several images to show exactly what I have got. Now my engine is supposed to be a VBB. Engine number on paperwork VBB2M #178603 but I am not sure now that I am delving. The gear teeth and ratios for the box and the primaries are in the original post I do have the engine out to change out the rear axle, shift cross,kickstart gear etc. Already done. While it is out on the stand I snapped a few shots so that you can see what I actually am working with. Obviously I have the two pin arrangement on the brake set up, it is now a matter of what I can do with it all. can I use the 8" wheel. As I try to attach images it appears that multiple attachments aren't possible so I will have to post individually. Image #1 General engine Attachments:
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Post by webrest on Oct 6, 2012 13:31:42 GMT
Image #2 Two pin set up Attachments:
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Post by webrest on Oct 6, 2012 13:34:48 GMT
Image #3 Engine view with wheel attached. Attachments:
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Post by webrest on Oct 6, 2012 13:38:24 GMT
image #4 Wheel attachment front view Attachments:
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Post by webrest on Oct 6, 2012 13:40:21 GMT
Image #5 Wheel only brake drum view Attachments:
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Post by webrest on Oct 6, 2012 13:49:24 GMT
Image #6 Case half markings Incidentally engine number is supposed to be VBB 2M 178603 Attachments:
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Post by sbwnik on Oct 6, 2012 15:56:44 GMT
I think a 150 Super back plate will go straight on that.
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Post by bryno on Oct 6, 2012 17:36:38 GMT
Yep, that is the way to do it, but problem is will end up with different wheels front & back, unless also fit a Super front hub and rim (VBB and Super have different styles of hubs and rims).
The VBB does not have 2 pin brakes as standard, so I think you may find a bit of a modification behind that back plate when you take it off..
Or
as you hinted, it is a different engine, what is the prefix on the swing arm? my guess is that it is not VBB2M it is VBC1M, a Vespa Super.
Post a pic of the front forks and we can see how the front was converted to work out how to put it back.
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Post by webrest on Oct 7, 2012 13:55:23 GMT
Ok guys here we go again. We are getting closer to what is going on. I feel like I am in a Sherlock Holmes mystery trying work this one out. The engine is definitely a VBB 2M See image. The question is why does it have the two pins if VBB's are supposed to have only one. I really thought it was going to be a VBC1m. As far as I can see there is no modification that has taken place anywhere. See the image in the following post. Clearly shows at least to me, that all is original. All components look as they should be for a fifty year old scooter. Anyway see for yourselves I may stand corrected. Dave ps Sorry image is upside down Attachments:
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Post by webrest on Oct 7, 2012 13:57:57 GMT
Image #8 showing the stripped back hub without backing plate. Attachments:
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Post by webrest on Oct 7, 2012 14:04:28 GMT
Image #9 Showing entire engine with stripped back hub without backing plate. Attachments:
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Post by bryno on Oct 7, 2012 17:05:24 GMT
Yep, its a mystery to me, all VBB's were 8" wheels, yours being a VBB2 is later than a VBB1, maybe they moved to 2 pins on later ones?
but they were certainly still 8" rims, so not sure how that would work. Need to take a look at a VBB wheel hub, check the internal diameter, if it works with those brakes, youre sorted..
I got rid of all my VBB parts but I'll check with the chap who has them now, see if he still has a hub he can measure..
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Post by kru251 on Oct 7, 2012 20:54:50 GMT
Interesting one this. Please do continue when you get more info!!!
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Post by bryno on Oct 8, 2012 10:14:58 GMT
Right, measured a VBB hub, internal diameter is about 126mm.
So if your two pin brake set up fit inside that you're laughing!
Otherwise, I think you'll need to search for a Vespa Super rear hub and wheel rim..
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Post by webrest on Oct 8, 2012 11:18:15 GMT
The plot thickens. Thanks for measuring Bryno. Don't know where you are measuring hub to get 126mm Here is the hub and wheel fitted to my scooter. As you can see by the measurements in green for the internal drum measurements are 153mm The outer ring measurement in purple are183mm [approx] Image #10 Attachments:
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Post by webrest on Oct 8, 2012 11:25:27 GMT
Now for the brakes. The linings O/A are 150mm in yellowThe backing plate O/A are 170mm in redso now I'm really wondering where we are at. Bryno, Is there any chance of a photo of the 8" hub and where you are measuring from? I really don't understand why mine looks completely kosher for a 10" rim as standard fitment yet it should be an 8" according to the VBB 2M engine number. Your're right Kru 251 it is interesting and we will find the answer. I'm not giving up. Attachments:
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) but I do care about good advice and engineering practices which is why I'm on the site! Sound like yours is not a simple job to convert to get good gear ratios, but I wish you luck and will follow the thread. Keep us informed of the results eh?
