i need something to help with lift. Was ridden in a snaffle and martingale all his life prior to me getting him. He’s not used to curb pressure and fights it constantly... I started off small with it and haven’t gotten anywhere. I have used the no hit bit, but sometimes he can lean on it. I have tried a port, which he was ok with, but anything with curb pressure is a no go. I’ve tried several types of curbs as well. Anyone have suggestions? He’s 11 so pretty set in his ways. 

Rosie Gag (chain mouth), or Goosetree Simplicity. 

Use a rope curb. I make them for my hackamores.  That is more of a problem today than before. Most of the horses today are ultra light headed.  Can't take curb pressure it scares them.  My hackamores came from this. Shallow mouth ultra light.  

Try a rope,about the size of a shoe string. 

So, have you had his teeth checked?  I would start with a leather or rope curb, place light pressure and reward for behaving until I could work up to whatever it is you need.  I'm not sure how long you've worked with the horse, but this could take weeks.  I too like a goosetree simplicity but, I've always graduated to a curb after a while, once they learn to run some will continue to push through.  This is a different situation-what would a person want a martingale on a horse until they're 11 years old for?? Is he high headed?  There's a hole somewhere, I would treat him like a 3-4 year old that is graduating from the snaffle and martingale and work slowly with whatever you choose.  As a side note, make sure his tongue isn't cut.......

Yes, teeth have been checked. I've started with a simple curb: biothane, leather, clothesline rope.  I started off super slow like you would a colt and nothing has worked.  He fights all the time.  The guy who rode him before just relied on the martingale for headset.  The previous owner isn't a very good rider, horrible hands . . . the whole 9 yards.  The horse has plenty of holes in his training, which I am in the process of addressing.  I just wanted some ideas on bits that I could hopefully try out so I don't have a fight on my hands every time I ride him, but I could still get my point across. 

My horse was ridden in a Tom Thumb prior to me. They did a little bit of everything on him, barrrels, poles, ROPING.  Ugh! In a TT!! EEK

Bought 900 bits (ok, maybe not quite) hated ALL of them.  Tolerates a chain mouth SOMETIMES.  

Found out he has a narrow pallate, and that it was damaged at some point...Thanks TT snaffle bit...and he had his wolf teeth on top of it. Was told he didn't have them...uh yeah, they were wrong.  Sigh.   

Got all of those issues fixed and he still hates bits.  

I ride him in a Jim Warner Hackamore.  No mouth pressure, but still has whoa.  

You might try a square or tiny twist snaffle bit to get him back to you if you're 100% sure it's the curb. I would guess there's something mouth-wise though that he's not liking. If he fights those, try a dogbone or 3 piece bit or chain. 

He tolerates the dogbone no hit bit ....

Any hackamore should help verify that there isn't an issue in/with his mouth. IF he still fights I would say you are right on the money with the curb pressure.   I hate to say it, but maybe a tie down to give him something to lean into?  If he's used to the pressure of the martingale, he might be getting too far ahead of himself which causes his reaction??  Good luck-hope you find a place to start!

Have you tried just not using a curb? I run my horse in a chain jr cow horse without one.

He tolerates the dogbone no hit bit ....

I wonder what an X-ray of his jaw would show. 

If he tolerates a gag, you could go that route.  Something small twist or square/square twist to get his attention. 

I wonder what an X-ray of his jaw would show. 

If he tolerates a gag, you could go that route.  Something small twist or square/square twist to get his attention. 

Hmm not sure.  He's getting some maintenance this week so I'll ask to get an Xray done

This^^ I was going to suggest the Goosetree Simplicity. We have a mare that is super light and very touchy/ratey  with curb pressure so I use a simplicity with no curb and it works great. 

If it is specifically the curb chain your horse is reacting to, you could try wrapping the chain in vet wrap to soften it a bit and make it wider which would distribute the pressure.  If you check out an english tack store they can have a padded roller specifically for this.(more effective than vet wrap)  The curb runs through and it would allow the bit to still work correctly with less of a sting as a straight curb.  

OMG!!  I have the same problem with my boy!!!  as soon as he feels that curb chain he shakes his head something AWEFUL!!!  The only bit that I've seen that he does well is a jr cowhorse but it has a chain. I put a leather strap WRAPPED ON VET WRAP AND STILL as soon as I put the breaks or feels a bit of pressure he shakes his head something baddddddd..... HE JUST HAD ALL HIS CHIRO, DENTAL, INJECTIONS BLAH BLAH BLAH DONE!!!

Have any of you ever run with a jr cowhorse WITH NO CHAIN, LEATHER STRAP?