Not a frequent tubular user, so bear with me.
went out last night with tubs inflated to about 130. pressure in rear seemed to have dropped substantially during a bumpy 1hr ride.
Inflated the tire after the ride and it doesn’t seem to be a slow leak- i can’t notice any drop in pressure overnight.
Is this unusual? Any suggestions?
“pressure drop?” Shit, I thought you were going to be talking about Toots and the Maytals, oh well.
Actually, I’ve noticed the opposite–my tubulars lose pressure while sitting around unridden, someone told me that is normal. Don’t know about losing pressure during a ride though.
It’s been decades since I rode tubulars, but it used to be that they came with two different kinds of internal tubes: standard butyl in the cheap/heavy “trainers” and latex in the pricy lightweights. The disadvantage of latex is that it isn’t completely airtight, the tire has to be pumped up before every ride. The pressure will hold for many hours or an all-day ride, but not for, say, 48 hours in the garage. But if your tire does fine overnight but loses pressure on a bumpy ride, this sounds to me like a possible tube defect at the valve stem attachment. This problem is not unique to tubulars; clincher tubes are sometimes defective in this same way. I recently had several Bontrager tubes with this defect, and I stopped buying that brand.
Toots and the Maytals inspired my Subject Line - I got that damn song stuck in my head last night after I noticed the tire was leaking!
Great band. I was royally pissed that i missed seeing them by, like, one day in Cape Cod during vacation last summer, and seem to be out of town every time they play here in Toronto. Maybe they could help me with my tubulars.
They might not be able to help you with your tubulars–but they sure know how to pull some tubes 
.