Shock for sip (sprint) fork conversion

I have just got a set of convesion forks and disk break (grimica classic) for my sprint. I did not relise they were pk so which shock absorber should i get

ps its a tuned 210 motor and I ride it around the lake district

Hally ive been looking around ebay but pk front ends are rare, they are 10 inch wheels though. Plenty of PX drum front ends available but make sure you get the 20mm spindle (the difference is in the alloy link, the 20mm later one has a casting with triangles in it but the early 16mm one is solid) I have a PX 200 drum front end and a Mk1 T 5 drum front end spare if you get stuck, they would need a clean up and or paint etc but anything from ebay will be the same unless you get it from a new bike. I prefer the shape of the PX disc wheel personally but its up to you. Mail me on [email protected] if you are interested. Otherwise keep an eye on ebay, ebid and scootertrader or the smalls in scootering magazine. Ps London was always shite, can`t recommend a cheap sprayer in your area, most custom sprayers are reputation based and good ones are worth the money but if it just plain paint you want try small car bodyshops that have their own sprayers, you will probably find one into bikes who will be interested in doing a scooter, or consider powdercoaters for plain colours as powder is far better than paint.

HALLY, see if you can get hold of a second-hand PK XL front fork assembly complete. Then use altogether, just swap over front mudgaurd. Its worth noting that the braking surface area on this set up, compared to a p2 is slightly larger. Then, when finances allow, just bolt on a disc assembly. You will benefit from a bitubo, but the pk set up will be far superior to the sprint.

Thanks twat i am a genius.

Use any shock for a pkxl, but would advise a bitubo due to extra unsprung weight, and heavier sring and damping rates required by the extra braking forces.

Agree with the shock problem, a pk is 255mm long a px is 330(approx. from top of mounting plate to centre of bottom hole. You can use a px drum setup, but with a pk shocker BUT the two bolt holes dont line up. on a pk the holes are closer together. youll have to drill the mounting holes whether you fit a disc or drum hub. Drill the bottom bolt hole. Bolt the pk shock to the top hole and use the shock itself as a guide to drill through the ali hub mount. JD

Cheers Beerace, Dumbass question but are they the same wheelbase/size? I had a PK50 in the early 80’s and seem to think they were possibly 8" wheels.

Also, any idea where I might pick up some such forks?

Also, know anyone who does decent spray jobs in the south(London-ish) that doesn’t entail re-mortgaging the house?

Also, why is London such a shitehole?

Cheers and Thanks,


sorry I have not been in touch.
I have not the forks in as i came of the bloody thing on a roundabout. ( i am to old for break dancing in the middle of roundabouts)

A local lad to me may has the forks you want. he deals in alot of second hand scooter parts his number is 07879 634928 (john)

I am still looking at which shock to get as there are two types of bitibo



using PX forks sounds like a good plan to me. The man who thought of that must be a genius!

Toddy, I’d be interested to know how much this set up has cost you. I put the T5 motor in my Sprint last year and could do with some better handling but I get the impression it ain’t cheap and theres no way I’m gonna sneak a set of forks past the wife… Also what exactly do you need, including cables and modifications etc…

Cheers, Hally

The px shocker does not fit. I found this out by buying one.

Hally I will let you know how much it cost and the parts you will need when I get all the parts.

I think the convertion forks are worth while because you get the correct race for top and bottom. They are also 20mm and pk so they are the correct size. There are a few extra parts that you will need such as shocker bracket and bushes and speedo drive and bits.

If you are on a budget fit the forks but use a standard hub backplate breakshoes assembly (sure px will fit). Then when the wife is not looking or you find a second hand disk fit it

One of my mates has used other methods using the px forks but it seems like a codge to me.


Any news on the cost of your complete set up Toddy?

It’s all sounding a bit complex with the shock etc… and modifications. Is there a simple bolt on way of sorting the shock? I don’t have the use of a garage, in London they cost as much as a bleedin’ house!

I’d liket to try and sort it out before Holland, don’t fancy goin all that way with the equivalent of a sponge for a front end!

Cheers, Hally

Use any shock for a pkxl, but would advise a bitubo due to extra unsprung weight, and heavier sring and damping rates required by the extra braking forces.

The cheapest way is to get a stock PX disc front end, they do appear on ebay for under £150 if you are lucky but more realistically you are looking at £200 to £250, use the forks & brake but sell on the headset if you want to use your sprint one ( I am not sure if you need to modify a sprint headset to use it on PX forks. Does any one else know?) Selling on the parts you don`t need should cover the cost of any new parts you need. You can use a Grimeca semi-hydraulic brake cylinder (around £40 from SIP) but as they are hard to get hold of at the moment I would recommend getting a Polini, or SIP, throttle tube and modifying your headset to full hydraulic with a motorcycle brake cylinder and using a quick action throttle. Look for my detailed disc brake conversion with thumb throttle on the Classic Board and the thread for the PX headset I have converted to disc with thumb throttle. Alternatively if you want to be really trick I can make you a new throttle tube from billet alloy, like the others I have made, and I make brake hoses to order. Email me on; [email protected].

St Hally, there are 3 disc front ends for sale on ebay at the moment ranging from £110 to £200. With any trick bits and/or modifying your sprint headset you should be able to do the conversion for under £300, plus you will be able to sell the PX disc headset to make some money back. Make sure if you want to use the PX disc headset that it comes with everything (light speedo, switches etc as that will hike the price up. Cheaper to convert your sprint headset.
Toddy, Bitubo are the best shocks to use, but the standard vespa disc shock is adequate if you are on a budget (not sure if the PK disc shock is the same as the PX disc shock but if they are different I would assume the PX shock will be heavier damped and sprung cos of the extra weight of a large frame) Check if the PX shock will fit the PK forks and you will have an instant stiffy up your front at standard prices. Make sure you check before you buy cos I do not know for sure.

Cheers for that Toddy, hope the scoots alright. Maybe the 210 is a touch fast for them winedy Lake District roads eh?

Get well soon,