thedonut

Has anyone tried the Impact Sherman idlers with the bearings? The shaft/mount seems to be too long causing misalignment with the roadwheels and sprocket. Attached is a photo which should make what I'm trying to explain clearer. Thanks.

WhiteWolf McBride

My Feedback: (3)

Hmmm...

I was thinking of getting a set of them now that the price is reasonable (the first ones on the market were $80 plus a pop!) but now that I see they are flawed, perhaps they aren't that much of a deal.

Is it possible you got a glitched set? Do both sides stick out, and can you measure it? (not very accurately done on a photograph, or guestimated on our own units)

Is it possible your inner idler wheel bearing is not pressed in far enough and is making the idler wheel stick out?

Just asking the Troubleshooting Questions that pop to mind that might cause the problem, so please don't take it personally (I'd ask it of anyone, even the veterans here)

Perhaps there a way to file off the outer edge of the chassis mount/casting so the idler wheel sits in closer to the chassis? Can you dismount the IMPACT axle and idler wheel to show if there is any leeway to do this 'make-do' fix?

I'd also check back with your supplier, whomever they are. They may not be aware of the issue, if the problem is an idler-mount thats too thick and pushing the idler wheel out too far. They may offer a discount, or replace it free of charge if the part is flawed.

WhiteWolf

thedonut

Hi WhiteWolf,

No offense taken on the troubleshooting questions. Same things I would probably ask.

Anyway, the bearings are pressed in as far as they could go. I'm considering filing mounts as you said as they are the parts that are too long compared to the original part. The shafts can be removed and those would have to be shortened too. New holes would have to be drilled in them (shafts) as well so they would line up with the grub screws that hold them in place.

I already asked Impact (mitosal.com) and am waiting for a reply.

Thanks for the suggestions WhiteWolf.

Monotheist

I have used both versions of Impacts idler upgrade. The first one where you had to re-use the plastic idler wheels and the new all metal version. I have to admit I was not overly impressed by the first as I couldn't center the hole you have to drill to fit the bearings properly so both idlers had a little wobble in them. I also wasn't a fan of the little set screw which required a screw driver to lock down as I managed to break that as well.

However the new all metal versions I am VERY happy with. Should have been like this from day one. Very heavy and feels very solid. Its also a bolt on solution so no mods are required to fit. The price is also very good for what you get in my opinion and I consider this a must have for all Sherm runners. My only advise is to be a little gentle on the set screw and you should be fine (doesn't need a lot of force anyway)

I never noticed this mis-alignment you mention and my tanks drive train is very smooth so perhaps the bearings are not seated properly. I have a bunch of stock idlers I will compare later if you like but regardless there have been no issues from me. Well done Impact!

Panther F

Good report there Monotheist. If there is a choice, metal is always the best way to go.

Monotheist

Double checked the Impact idlers against the stock Tamiya ones and there identical.

Heres a pic of the new all metal ones installed on mine. As you can see no track misalignment at all.






Heres my older Impact (left) against stock Tamiya (right) to compare axle length. Note the upgraded hex bolt due to the other stripping out.

modeltank

mine's working fine and running smooth too.

Installed it about 2 month ago.

Here is their youtube about the idler
http://www.youtube.com/watch?v=T0yGN...e=channel_page

thedonut

Thanks for the inputs everybody. Looks like I got a lemon then. Posted another pic (Impact on the left, Tamiya on the right) showing the shaft inserted into the mount as far as it can go (no set/grub screw). Shortening the shaft will mean filing the mount and drilling another hole in the shaft that lines up with the set screw. []

Monotheist

Dont cut anything just yet. It might just need a little tapping to get it in place. If that doesn't work measure the length of the axle shaft and I will compare to mine (...and no sarcastic comments about comparing shafts please )

WhiteWolf McBride

My Feedback: (3)

Thedonut:

Looks like I'll hold off until the retailer gets back to you. I don't want to have to deal with a lemon... I've done it twice, first time I took a loss on the part cause he lied about the casting material (was pewter, not nickel silver) and the second, it took 2 months to get the mal-formed part replaced.

Would a rep from the retailer care to speak up and confirm all remaining stock is being checked, wherever it is in the distribution chain (apart from postal transit) and that any 'out-of-whack' parts ~will~ be replaced at no charge?

If they will do that, I'll order.

thedonut

Hi WhiteWolf,

Two emails to Impact/Mitosal and still no reply. No problems getting a reply from them when I was inquiring about the parts, though [sm=greedy.gif]. Oh well, we'll see.

thedonut

thedonut

Finally got a reply from the supplier:

"As to regards to your question about the difference in width between the Tamiya and Impact units, we have double checked with IMPACT Upgrades and they re-state their position that they deliberately built their Sherman Idler wheel kit as such, rather than just simply copy the Tamiya's item. As according to their testing, they found that the Tamiya original design, designed in 1974!, had some flaws or rather more room for improvement.

The widening of the rear idler arms has the net effect of a 'slight toe in' similar to a car wheel alignment, this helps with better straight line running, as with the original Tamiya tracks, the tank might want to pull to either the left or the right, also with frequent running in the grass or sand, the original Tamiya tracks might rub against the lower hull or create a build up of dirt/grass and sand which again might get caught in the tracks."

So what does that make everyone else's idler that have no misalignment on this thread? Flawed? [sm=wink_smile.gif] Can't return them too since I painted them already []

thedonut

Hi everybody,

Before I demand even just replacement of the mounts from the supplier, can you help me out on a couple of things:

The only toe-in is between the idler wheel and last road wheel which is elevated. The part of the track that makes contact with the ground is still straight so that myth is busted. Did the real Sherman have toe-in? Make sense?

It was never stated in the literature for IMPACT to "re-state" that the mounts were wider in diameter. The only description in the page was

"The Tamiya 1/16 Sherman stock plastic idler wheels had always been one of the wear and tear issues, where the shaft will wear the centre hole and causes the circular hole to be in oval shape after a long period of running. Impact's Idler wheel set for the Sherman will resolve this issue"

Would you have bought them had you known it would cause your tracks to be misaligned?

Anyway, I tried it as the supplier said and found there is tension between the idler and last road wheel because of the misalignment (duh). It feels like the track wants to come off. Running it will most likely result in exactly that and put extra stress on the tracks and gearboxes.

I am worried that I will be stuck with a $40 substandard part. I'm just hoping they would send me replacement mounts as that is where the problem is. Is that too much to ask?

Thanks guys!

Monotheist

Well if theres built in toe in on these new idlers then it sure as hell aint on mine. Check the middle pic I posted above and you can clearly see that the idler is in line with the road wheels. Just to be 100% sure flip the idler wheel 180 degrees on the axle to see if that doesn't improve things. There might be a slight offset built into the idlers so give it a try...

pcomm1

"The widening of the rear idler arms has the net effect of a 'slight toe in' similar to a car wheel alignment, this helps with better straight line running, as with the original Tamiya tracks, the tank might want to pull to either the left or the right, also with frequent running in the grass or sand, the original Tamiya tracks might rub against the lower hull or create a build up of dirt/grass and sand which again might get caught in the tracks."

Not to worry, Impacts above statement is true per my past build experience with a stock 105 Sherman f/o. Use the parts, they will work. I got the same parts from Mitosal in April 2009 and they look just like yours and tested good on my new Sherman build running the Impact T-66 tracks.

John

bowlman

I have the same upgrade going in the firefly good thing this is not a problem .

Thanks
Jimmy

WhiteWolf McBride

My Feedback: (3)

Ok...

Monotheist, pcomm1, and bowlman are all saying their idler sets do NOT have the alignment problem shown in thedonut's image in post #1? Is this a correct assessment?

HOLD ON A SECOND... take a look at Monotheist's idler axle image showing the re-tap for the bolt (post 6, image 3) doesn't the axle look like its at a ~slight~ angle? (especially compared to the stock one)

This may sound odd, thedonut, but try swapping your mounts left-for-right, and see if the axles go a bit toe-in. You may have them on the figurative 'wrong sides' and hence you are getting a nasty 'toe-out' look. Its what I'd try...

It would help if IMPACT/Mitosal explained HOW they got the effect they wanted - is it a ~slight~ angle on the axle shaft, or does the mount actually stand out further? Anyone speak their language (clearly as English isn't their native tongue) and able to get an answer that explains WHAT they did to achieve their aim?

If its an angled axle... why in HECK don't they say so, and why aren't the mounts marked left and right? Another example of incomplete/inaccurate translation of Oriental manuals (Tamiya still has flaws after 30+ years!)

Again, I'm waiting on buying ANY IMPACT products until they get their act together and give us some answers... preferrably in person, not second-hand. (those T66 & T81's look tasty... but with this issue... *sigh*)

WhiteWolf

thedonut

Both mounts are identical from visual inspection. Mounts are really just wider. I'm not a mechanical engineer but, I think if you wanted toe-in with a tank, the road wheels should gradually get farther apart from the front towards the rear of the tank, right? If it's just the idler and the last road wheel then the only "toed-in" part of the track would be the portion that does not even make contact with ground at the rear of the tank. [sm=confused.gif]

Monotheist, pcomm1, and bowlman are all saying their idler sets do NOT have the alignment problem shown in thedonut's image in post #1? Is this a correct assessment?

...exactly. Bearings properly seated and shaft all the way in the mount.

Monotheist

WhiteWolf McBride, there is no toe in on the impact units. The reason why my pic may indicate as such is because I was in a hurry when I took the pic and never tightened the locking screw so the axle is just sitting loosely in there. If you look very closely you will see the gap on the left hand side where the axle inserts into the main mount which is not present on the right side.

All I can really say is I believe these new idlers are are a 100% improvement over stock and a 60% improvement over the old Impact units which used the existing plastic idler wheels. Im extremely happy with mine and im a really fussy dude so I say just buy with confidence.

pcomm1

Back to basics Impact Idler assembly check list and tips:

1. Look again at your own parts, there is about a 1 degree of lean (toe in) if you assemble the unit correctly. That lean should point forward as to the front of your Sherman tank per photo 1.
2. The shaft has a flat spot machined on it. Align that flat spot so the set screw hits it per photo 2.
3. Place your bearings to the inside per photo 3.
4. The units are slightly wider so you can run the slightly wider Impact T-66 metal tracks.
5. The idlers work fine, and yours will too, hang on your tank and run it.
6. Other tips, polish the shafts and get them smooth and grease well before assembly.
7. Enjoy your parts, Impact stuff works.

Good luck, John