First Vectrix!..

How do you like the Diablos so far? I had a Diablo on the front of my old bike and I liked it, but I personally can't tell a difference with the OEM Pirelli, to be honest. I read the Diablo is supposed to be grippier and better in dry and wet. What's your feel?

I am also looking to minimize or eliminate the annoying handlebar wobble at around 40mph speed that I have had on both my bikes. Someone told me that wobble disappeared from him when they switched to Michelins - I think mine are related to the Pirelli tires, with their wavy and bumpy thread pattern...

I've chosen for my Vectrix a Pirelli Diablo SC, following recommendations from other rider with quite some miles of Vectrix riding.

I have those Michelins fitted to my red Vectrix and the original Pirellis fitted to the blue one, and I much prefer the handling of the Michelins.

They are relatively new and do make a loud squeaking sound as they roll over the piece of vinyl on my garage floor, and the rubber on the rear tyre makes an unusual noise under hard braking if it skids, which I can only describe as a much lower pitch than the tyre screech I used to get from the 18" Avon rear tyre my CB750 Honda which I wore out in less than 1000 miles.

I haven't really tested the City Grip tyres in the wet as I prefer to stay dry (and keep the bike clean) but I can't fault the grip on a dry road.

I opted for Michelins on the Vectrix because I have been driving Citroen cars on Michelin tyres for decades and they always seem to grip incredibly well when braking in the wet and I am confident that I can always stop quickly in the wet when needed without activating the ABS.

When the Blue one needs new tyres I will definitely be fitting Michelin tyres on that one too.

Alan

EDIT: Picture link repaired

How do you like the Diablos so far? I had a Diablo on the front of my old bike and I liked it, but I personally can't tell a difference with the OEM Pirelli, to be honest. I read the Diablo is supposed to be grippier and better in dry and wet. What's your feel?

I'm very careful when I drive a motorcycle, because I already know the taste of tarmac... it costed me a broken elbow, so I don't explore too much the limits of the tires / bike...
The previous tire, the original Pirelli GTS, was at the end of life when I bought my VX-1, so this Diablo SC is obviously much better!

Because at the front it has a Michelin CityGrip, I also was inclined to change the Pirelli GTS for a Michelin CityGrip.
But, two persons that I know which have VX-1s advised me to choose the Pirelli Diablo SC because they consider it very grippier, both in wet and dry.

I am also looking to minimize or eliminate the annoying handlebar wobble at around 40mph speed that I have had on both my bikes. Someone told me that wobble disappeared from him when they switched to Michelins - I think mine are related to the Pirelli tires, with their wavy and bumpy thread pattern...

The previous owner also complained about the wobbling.
According to him, changing to the Michelin CityGrip solved the problem: Uma Vectrix catalã em Lisboa

Personally I do agree with him... I also agree that the fork is a bit harsh, but my previous bike was a Yamaha XT600E...

I opted for Michelins on the Vectrix because I have been driving Citroen cars on Michelin tyres for decades and they always seem to grip incredibly well when braking in the wet and I am confident that I can always stop quickly in the wet when needed without activating the ABS.

Another Citro Lover! Cool! :D

I have a Citro AX GT, 5 door, from 07/1993, hence with the TU3 injection engine... it's only 75cv, but the 800Kg of curb weight make it very nimble! }:)
I hope to fully restore it and also add some spice to it...

Thanks!

In you photo, the Red bike seems to have the optional lower seat and the blue one has the regular? Do I see right? Could that have anything to do with the difference in handling, as you are sitting lower on one bike vs. the other?

I have those Michelins fitted to my red Vectrix and the original Pirellis fitted to the blue one, and I much prefer the handling of the Michelins.

Alan

The Red bike does have the lower seat, but this bike also had the original Pirelli tyres which were wearing low in the middle and I ended up replacing them after 9 months of intermittent use. When I fitted the new Michelin tyres onto this bike I immediately noticed the difference in the handling.

The lower seat is much safer when stationary at lights and junctions etc. (especially on a steep hill when you don't have long legs) but I actually prefer the height of the normal seat for longer trips, as the padding is more comfortable and it also eases the bending of your legs when your feet are on the footrests.

I find the Pirelli tyres (on both bikes) caused (and on the Blue bike they still do cause) the handlebars to want to turn in too much as you enter bends. I originally though the "oversteer" effect was due to the worn tyres I had replaced. But since I acquired the Blue bike I find it behaves the same as the red one used to, but the tyres on the blue bike appear to be very evenly worn and still have lots of tread, which is not really surprising as the bike had been ridden sedately by the original owner and had covered less than 1,150 miles when I bought it back in March (that's ~165 miles per year).

Perhaps the over-sensitive castor effect that the Pirelli tyres seem to induce, which causes the automatic movement of the steering to counteract the bike's angle of lean, might explain the steering wobble that so many owners have experienced.
On the Michelin tyres I can release the handlebars at any speed and they remain nice and steady as you would expect them to, but I wouldn't feel so confident doing this on Pirelli tyres.

Alan

Thanks, good info! Did you by chance replace only one tire first to see if it makes a difference? Both my front and rear tires are still in good shape. And on top of that, I have spare front and rear wheels with mounted and balanced OEM tires from the Vectrix auction. It will be nice if replacing only one of the tires would solve the wobble, so I don't have to throw away both of my perfectly good tires...

Now that I think back, I remember that I preferred the turning on my first Vectrix noticeably better than that of my second one. The first on came with a Pirelli Diablo in the front, stock in the rear. The second with the stock Pirelli front at rear. The first bike was considerably more eager to lean into the turn (in a good way), where I have to coerce the second bike a bit more. But both have the wobbly handlebars to about the same degree: between 20 and 45mph, approximately. Faster or slower than that I can let go of the handlebars and the bike stays stable and smooth.

Oh, and what is that small cylinder near the caliper/front fork on the red bike on your photo?

Thanks, good info! Did you by chance replace only one tire first to see if it makes a difference?

Oh, and what is that small cylinder near the caliper/front fork on the red bike on your photo?

No, I changed them both at the same time, but I would expect the front tyre to be responsible for the effect on the steering and also any steering wobble you may be experiencing with a correctly balanced wheel.
Incidentally, I did not remove the existing balance weights from the rim when I replaced the tyres as these wheels won't fit on the electronic balancer that I use. So I decided to leave them on to see how they were, and the balance seems fine as there is no discernible wheel vibration throughout the entire speed range.

I seem to recall reading somewhere that a top box fitted to a Vectrix can cause steering wobble, but I'm not convinced that that would be the cause.

If you look at the Pirelli tyre that is fitted to the Vectrix, you will notice that it has a continuous wavy line right around the centreline of the tyre:

I think the wavy line causes a slight side to side pressure variation between the tyre and the road surface as it rotates which could induce steering wobble if combined with a sensitive castor steering effect at the right frequency. Whereas in comparison, the Michelin tyre has a 1/2" wide solid section directly around the centre of the tyre, which should help it to roll nice and straight producing a well centred castor action.

I will try to explain my theory, which is purely based on observation and experience. I have no actual proof of this whatsoever, but I am convinced that the wavy line is the culprit.

If you placed a laterally balanced loose wheel with a Pirelli tyre in an upright position on a level flat surface it should try to tip one way or the other depending on which side of the centreline the gap of the wavy line was positioned.

So, if the typical contact width of the tyre in an upright position is say 1/2" and you have a 1/4" gap on one side of the centre line and 1/4" of rubber on the other side it must have an adverse affect the steering as all the force is acting to one side of the centre line, and as the tyre rotates, the exerted force on the tyre moves across the centre line to the opposite side.

Although it now seems very obvious to me, it's very difficult to try and explain in writing what is actually happening where the wavy line meets the road surface.

I hope you've been able to understand at least some of what I've tried to explain.

Anyway, the cylinder on the fork leg is just a tax disc holder bolted to the brake caliper bolt:

In the UK, we are no longer legally required to display a valid tax disc as they have gone paperless and stopped issuing them, I just haven't bothered to remove it yet.

Alan

EDIT: Picture links repaired

The lower seat is much safer when stationary at lights and junctions etc. (especially on a steep hill when you don't have long legs) but I actually prefer the height of the normal seat for longer trips, as the padding is more comfortable and it also eases the bending of your legs when your feet are on the footrests.

And how about the backrest ?
Since you seat lower, hence the backrest supports more of your back, does it become more comfortable for your back ?

Perhaps the over-sensitive castor effect that the Pirelli tyres seem to induce, which causes the automatic movement of the steering to counteract the bike's angle of lean, might explain the steering wobble that so many owners have experienced.
On the Michelin tyres I can release the handlebars at any speed and they remain nice and steady as you would expect them to, but I wouldn't feel so confident doing this on Pirelli tyres.

I believe you are spot on!

I recall replacing the original tires - Bridgestone Turanza ER30 - of my car by a set of Pirelli PZero Nero and at first I noticed a strange feeling in the steering wheel... at the time, I inputed that to the thread pattern of the Pirelli's...

(...) I have spare front and rear wheels with mounted and balanced OEM tires from the Vectrix auction. It will be nice if replacing only one of the tires would solve the wobble, so I don't have to throw away both of my perfectly good tires...

Don't forget that the tires loose properties over time and that's why the manufacture date of them are very important to observe!
Most of the promotions of tires are because they have been too long in storage.

I seem to recall reading somewhere that a top box fitted to a Vectrix can cause steering wobble, but I'm not convinced that that would be the cause.

Mine VX-1 has a Givi V46 top box mounted and I don't feel wobbling... only more drag...

Although it now seems very obvious to me, it's very difficult to try and explain in writing what is actually happening where the wavy line meets the road surface.

I hope you've been able to understand at least some of what I've tried to explain.

Great explanation!
It was perfectly understandable for me!

And how about the backrest ?
Since you seat lower, hence the backrest supports more of your back, does it become more comfortable for your back ?

To be honest, I haven't really noticed any difference with the back support.

I seem to recall reading somewhere that a top box fitted to a Vectrix can cause steering wobble, but I'm not convinced that that would be the cause.

I have just found the details in a document entitled "Hidden features & Common Diagnose.pdf":

Symptom
The handlebar vibrates and moves roughly (shimmy effect)

Problem Verification
If the bike has a cargo box, remove it and check again

Possible Problem/Issue
Check the tire pressure

Solution
Check the tire pressure - Remove the cargo box

Great explanation!
It was perfectly understandable for me!

I'm glad you were able to understand my explanation, if only it could be explained in a simpler way so that everyone could understand.

For anyone who was not able to understand my initial explanation, imagine riding along a 3mm wide steel guide rail which causes the steering to go from side to side as the wavy groove in the tyre is persuaded to follow the straight line path of the fixed guide rail.
I realise it's not really the same, but I think the resultant shimmying effect on the steering/handlebars would be similar.

Alan

EDIT: Picture link repaired

Bikemad, your explanation is clear to me too, but I have my doubts about it: if the wave pattern is the culprit, its "frequency" should match the frequency of the wobble of the handlebars. Now, I have no way to measure the handlebar wobble frequency, but I think it is slower than the wobble that would be caused by the front wheel's curvy thread pattern. Of course, it could be reacting to a "harmonic" (i.e., a multiple) of that frequency...

But in my case, I just found out that my rear rim is slightly bent sideways and it's rotational frequency seems more like what the handlebars are doing. I'll be replacing the rear tire/rim soon and report back if that changes anything.

I don't doubt the Michelins ride smoother - the Pirelli GTS have an obvious oscillating pattern of "hills and valleys" along the curvy center groove, if you look tangentially at them (sorry for the "tech-speak")...

Good choice! I whish they were available in 140/70-13 size for the rear. After reading the confusing Michelin tire infomercials on their web site, and comparing the Power Pure SC vs. the City Grip, I am confused. It mentions the Pure are somehow related to some of Michelin's sportier full size tires, the chart says they are intended for "sport commute" and the City for "functional commute". The City has a check in the "wet" column and the Power doesn't, indicating the City is better in the wet (which it might be, looking at its aggressively thread cutouts).

Anyhow, since everyone is so happy with the City Grip (plus they are cheaper than the Pure, especially for the rear), that might be the wiser choice for the stock size...

I ended up buying the Michelin City Grips from MyTyres.

The current front tyre is barely worn and I have not noticed any wobble at 40mph, not that I have really looked for it to be honest. For the money though, I may end up purchasing a front Michelin too.

http://www.mytyres.co.uk/cgi-bin/rshop.pl?dsco=110&Cookie=tyrecomp&details=Ordern&typ=MOTO-D-112950&ranzahl=4&nichtweiter=1&pk_c...

http://www.mytyres.co.uk/cgi-bin/rshop.pl?dsco=110&Cookie=tyrecomp&details=Ordern&typ=MOTO-D-112951&ranzahl=4&nichtweiter=1&pk_c...

Hi. I've just become the owner of a 'dead' VX-1 nmh bike. I saw your entry titled "First Vectrix!.." and hoped you could point me in the right direction regarding the temp' sensor boards.
I discovered several of my boards are corroded away, and was hoping to attach an easy to find thermistor to the existing board. I gather that the existing boards use a "0805 10k ohm ntc thermistor", is this correct?
I measured each existing sensor and they don't register until in M ohm scale, so either they are all faulty or I have the wrong info.
Looking at the existing boards it looks like a track on the board goes behind the centre of the component from the large tab area. Is this to conduct heat to behind the component, or is the component 3 legged ???

Any help/response would be greatly appreciated.

Do you know of any skilled enthusiasts in the UK who would like to chat???

Regards ... Dave

The Vectrix sensors are simple thermistors which form a voltage divider with another resistor on the mother PCB. They are accurate to within about +-2degC. These are 10K thermistors at 25degC.

Hi Dave, perhaps it's your ohmmeter that is not measuring the resistance correctly as they should all be ~10K at 25 degrees C.
Can you borrow another meter from somewhere to double check the readings?

Check out this post for further details of two different types of temperature sensors.

One of my two NiMh Vectrix would not charge when I first bought it, but it is now charging nicely with both temperature boards completely disconnected from the main harness.
I am using The Laird's Modified Software (Only suitable for use with the silver ESD chargers) to prevent the temperature light from flashing continually.

Alan

Apologies for the thread hijack - but as new users can only post to existing threads and not create new ones (and I can't find a "welcome" or "introductions" type thread in the general section), I need to post into an existing thread, and chose one that is as close to "on topic" as possible.

I too have just purchased my first Vectrix. I haven't ridden in 11 years, and feel very unstable on it, but I'm sure a few hours, and I'll be fine.

The bike is in working condition, but has never been registered (Bought as a parts bike by another member of this forum), but I have booked in for a Roadworthy Certificate in 2 days time.

I'm going to get used to the bike first, but apparently the battery is on its last legs (22Ah of 40Ah original capacity - 43S LiFePo4), and sagging so that it can only provide 10kw. My intent is to eventually boost the battery pack with a very low internal resistance battery type (Probably LTO, but if I can't get a good supply, high C-rate LiPo). My hope is that the boost will last until I move to the UK (from Australia) in 2019.

I'm not sure how many posts, or how long until I get approved to write up my first post with all my questions, but I don't want to foul up this thread with off-topic talk, so I'll leave it here for now, but I am obviously keen to be an active member of this forum. I have a fair bit of experience building electric push bikes and own a PHEV, but have never worked on a Vectrix before, so will have lots of questions.

Cheers!

Ken