HST running issue

[ColinB]

I don't know if this is much use but I thought I would share it with you. I have been having issue with my Hornby HST not running that well, not getting up to a reasonable speed and the traction tyres slipping. So I changed the traction tyres still no joy, then I checked the back to back wheel spacing. It is an old ringfield motor based HST but does have a 5 pole motor. Anyway it worked out that the back to back wheel spacing was way out. Once I had modified it, the loco runs lots better. The only thing I can figure is if the spacing is wrong, it is proberly running on the edge of the traction tyres losing grip. It even works without the extra weight I put behind the motor. I am surprised though because nomally if the spacing is wrong it normally jumps when hitting the points. I had to add small nylon spacers to get the back to back measuement correct, I think Hornby normally use the "press on" wheel gears to do the same, I assume my loco had lost them. Anyway small nylon washers seem to work better.

[STG]

I do have similar issues, however, find that when the back-to-back is correct, the cogs can sometimes not gauge properly and slip. I'm yet to put the back-to-back guage back to what is should be with washers to stop this

[ColinB]

@STG Yes you would, I had that issue, that is why you need the nylon spacers. You put them on the axle on the undriven side of the axle. They take up the slack, in my case it was about 1mm which is a big enough gap to stop the gear on the wheel engaing with the drive gear.