Spring bar selection
DW and I are looking to upgrade to a trailer with a published tongue weight of 1100lbs. GVWR 9500lbs. We currently have a Reese Straight line 1200lb/12000lb capacity. Are the 1200 lb. bars stout...
Forum Discussion
Hi Ron,
Thank you for your reply.
I followed your link to Airforums, those that posted when I looked didn't add much at this point. Maybe more will come in as time goes by. And yes, I too have heard on the Air Stream that a heavy spring truck and or WD bar can cause A frame issues on some of the trailers. I'm assuming the lighter campers.
Your explanation I agree with assuming that bar deflection is proportional for the given TW rating between bar sizes. I do not know if all brands adhere to this.
I have not yet convinced myself that on the higher TW's, approx 1,200# to 1,700# or higher that it is a good thing to run WD bars of half size. The dynamic conditions are the concern. Running a 1,600# TW with 800# WD bars makes me stop and think.
In my case, I have the parts to actually do this if I choose too. On my truck with that heavy a TW, if I stop quickly the back of the truck will drop quickly when I have no WD bars on. With 1,700# bars on, I get a small drop. If I put my 800# bars on I would expect more drop then the 1,700# bars. I only do this in my drive way with no bars on, but I can feel the bob up and down of the back of the truck very much. Out on the highway the conditions will be more dynamic. The 800# bar will flex more than a 1,500# or 1,700# bars would given the same situation. The TW mass is there to cause this. This is only one case of the dynamic conditions.
This comes back to, if we knew the working limits of the WD bar before we approach the yield point?? If the bar can flex to meet all of the dynamic conditions and not exceed the working limit, all is good. That is the part I'm still thinking on.
At this point I feel more confident in using bars for the full TW and only adjusting them lighter verses the lighter bar in the heavy TW's.
Thanks for helping me think some more on this. If I think hard enough on this, I sense an experiment coming to help prove myself right or wrong...
Thanks
John
Thank you for your reply.
I followed your link to Airforums, those that posted when I looked didn't add much at this point. Maybe more will come in as time goes by. And yes, I too have heard on the Air Stream that a heavy spring truck and or WD bar can cause A frame issues on some of the trailers. I'm assuming the lighter campers.
Your explanation I agree with assuming that bar deflection is proportional for the given TW rating between bar sizes. I do not know if all brands adhere to this.
I have not yet convinced myself that on the higher TW's, approx 1,200# to 1,700# or higher that it is a good thing to run WD bars of half size. The dynamic conditions are the concern. Running a 1,600# TW with 800# WD bars makes me stop and think.
In my case, I have the parts to actually do this if I choose too. On my truck with that heavy a TW, if I stop quickly the back of the truck will drop quickly when I have no WD bars on. With 1,700# bars on, I get a small drop. If I put my 800# bars on I would expect more drop then the 1,700# bars. I only do this in my drive way with no bars on, but I can feel the bob up and down of the back of the truck very much. Out on the highway the conditions will be more dynamic. The 800# bar will flex more than a 1,500# or 1,700# bars would given the same situation. The TW mass is there to cause this. This is only one case of the dynamic conditions.
This comes back to, if we knew the working limits of the WD bar before we approach the yield point?? If the bar can flex to meet all of the dynamic conditions and not exceed the working limit, all is good. That is the part I'm still thinking on.
At this point I feel more confident in using bars for the full TW and only adjusting them lighter verses the lighter bar in the heavy TW's.
Thanks for helping me think some more on this. If I think hard enough on this, I sense an experiment coming to help prove myself right or wrong...
Thanks
John
