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Old 12-08-2004, 03:04 PM   #8
Denny_A
Former TM Owner
 
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Join Date: Jul 2002
Location: Greenville, WI
Posts: 517
Default Re: TM Towing Spreadsheet

Quote:
Originally Posted by MountainCamper
Denny:

Good additional clarification on the importance of axle / wheel weights also, as a follow-on to suggestions from Ray. I remember reading something similar to this, I believe it was a post from you, back in late 02 or there abouts.
Yup, that was me. I worked with the TM engineer for several weeks trying to understand why the GVW was such that the axle would be overlaoded when using a WDH. That's where the "unsprung" wheel weight (not being included) surfaced. Their position is at odds w/Dexter and the official definition of Gross Axle Weight Rating(GAWR). Dexter do not dispute TM specifically (I asked), yet only support the official def'n of GAWR. I.e., GAWR is referenced to the load at the tire/road interface! A TM - Dexter GAWR application dichotomy.

Quote:
This calculation process seems to lend itself to a fill-in-the-blank calculator for a TM base model, with options ordered, and supplies & expected personal accessories to be carried, being towed by xxxx vehicle with it's specific GCWR, GVWR, GAWR, etc. Sounds like a straight forward exercise in Excel spreadsheet engineering with a few imbedded formulas. Anyone know if this has been tried before, specifc to TMs, either for current year models or past years? I found one such spreadsheet for a weight / tow calculator online (I'll find the link somewhere) but I don't believe it took into account the WDH weight transfer, axle loading, and I think it assumed sea-level altitude and a full-sized trailer box (wind resistance, etc), but also left out a few other items I think.
A spreadsheet "tow calculator" might be a bit of a challange, if one were to include all models and the last 2 to 5 yrs production. Different GVW and different axle GAWR's and changes in tire size, load rating of some models would have to be accounted for. Also, the issue of parasite drag (wind resistance) would be difficult to consider, since there may not be any established baseline for the TM box (all have nearly the same drag coeff.). Due to the low profile, I don't believe the effect of wind resistance has even been considered by TM.

However, there are enough geeks in here that would love to have a new toy (spreadsheet) with which to fool around. I developed my own customized tongue weight load graph awhile ago. By loading my hitch with weights, up to 500 lbs, and plotting hitch receiver deflection vs. load, was able to determine tongue weight by measuring pre/post load heights at the hitch receiver. Why - just for grins!

Quote:
Would there be any interest .......: "What TM model can I safely tow with my xxxxxxx TV?"
Maybe. TM has published a comprehesive Towing Guide (from Trailer Life) on their website - here.

Denny_A
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