New wheel balancer and tyre changer

Anybody remember me talking about this...

Hofmann megamount 513

Well since we got it I must say it has been tricky to use when putting tyres on the rims. No matter how much soap is used around the rim and tyre sometimes the bead appears to get stretched when fitting the last twelve inches or so.

Today I was asked to fit a new tyre landsail to a Renault with TPMS. Removing the tyre was no problem and the TPMS valve was not conntacted so no damage occurred. I fitted the new tyre which went okay until the tyre seemed to become tighter over the last few inches, but the tyre did pop on the rim.

There are no tyre levers used on this machine, the machine has its own built in lever for removal. 

After inflating the tyre to the recommended 32 psi nothing was obvious. I then put the wheel and tyre on the balancer above^^^ in last post and balanced the wheel and tyre assembly. Again no problems observed.

The customer collected the car and drove it about 10 miles. I came back off my lunch and the boss asked if I had a sat nav? The tyre had deflated he said. So I went out to the car and she told me that the TPMS warning lamp came on and the tyre immediately deflated.

I got back to the garage and tried to inflate the tyre but the tyre was leaking badly on the rim. I removed the tyre and noticed damage present to the bead area. I checked the tyre valve which seemed okay and untouched. I put another tyre on and on the last six inches or so the tyre (heavily soaped) seemed tight and then popped onto the rim. The tyre machine does give this impression of being tight like this on most tyres I fit. I inflated the tyre and did not notice anything wrong. I then put the wheel and tyre in my boot and took back to the customers car and fitted. She then told me that the TPMS warning lamp did not switch off. As I remember the operation at the garage the TPMS warning lamp did extinguish when the engine was started, but it does not seem to have done this time?

She said to me as she was walking off that she would call to the local garage and put some more air in the tyre? Before I could speak out she'd walked off from my car. I watched her drive off in the Renault with a properly inflated tyre. When I got back to the garage she rang me on my mobile saying something about the valve leaking? Her phone then went dead. I tried to ring her back but her phone went straight to answer phone. I left her a message. Later about six o clock she rang my mobile again and explained that the valve was leaking? Some guy was there with her and he said when he moved the valve side to side the valve leaked!

I can't recall seeing anything wrong with the tyre valve stem when I looked at it and I certainly could not renew it because of its design (TPMS), however I do normally fit a new valve core, to which I did on this occassion. 

She is bringing the car back tomorrow and hopefully she has it recovered as I recommended. 

Although this guy with her advises the valve leaking in my mind I'm thinking the tyre bead could have been nipped. It just seems odd that the tyre did not leak straight away the first time round, taking time at the garage before collection and then driving the car ten miles before the tyre lets go, and then the second time I take the tyre and wheel the ten miles and is fully inflated at the time I'm there fitting it, and then within the hour she is on the phone saying the valve is leaking!

This tyre machine I think needs throwing out.

I don't recommend anybody buy this make and model of tyre machine ever. Snap On told me at the point of delivery of the machine that he new garages that had purchased this make and model only to never use it. Our new mechanic has also damaged a tyre on this machine recently as well. Its a terrible machine. 

My busiest centre (>1k tyres per month) has a couple of these machines, not with the lever less option though. No issues for us, except bead breaker seals which have been done twice under warranty.

Couple of smaller branches have them too.

Thanks its not valve damage that is occurring, it is the bead of the tyre that is being overstretched. The reason this appears to be occurring is because the lever operation when adjusted to the rim seems to far away. Guessing there is about an inch or more away and above the rim which I can't bring closer to the rim. Some tyres even when the bead is sat deep in the central area of the rim where the rim diameter is the very least it can be still stretches the bead too much on some tyres. The cure for me is that I'll never use that machine again. 

I agree, some BMWs spring to mind, but not Renault Twingos 

It actually depends on the rim design not so much the vehicle. What size rim?

Even with automatic tyre machines you’ve still got to put some effort in to fit tyres .

Only a 15 inch standard rim really. I'll take a photograph of the problem I'm having then hopefully we'll all see the same undertanding of the problem I'm faced with. 

Have you spoken to Hoffman about it? If the fitting head is an inch away from the rim, you’re right, there is something very wrong but probably easily explained.

No dwain that is down to the boss and I have previously advised him of the problems.

I understand what your saying and on wheels without TPMS I say depending on the rim design inside a couple of inches should be okay, but TPMS we need to be a little more thoughtful.