rather than a sleeping bag inside a bivvy bag. is it a good idea.

I 'spose if you've ridden yourself to exhaustion and your going to crash straight out, Aye. But I like to snuggle up under my quilt and if I'm not totally wiped out I need some comfort to get a good kip. Plus I think my quilt weighs less than my down jacket and a set of medium weight thermals.

I tried lightweight insulated trousers and jacket inside a bivi bag a few summers back, I was cold, but (trying to be polite) I'm a bit learner than you and feel the cold. I also didn't have a mat.

I'd say give it a try in the garden or take a backup sleeping bag on a test bivi. I might try it again with my Neoair this summer.

ton wrote: ↑Thu Apr 22, 2021 9:30 pm rather than a sleeping bag inside a bivvy bag. is it a good idea.

Yes.
I use Gore Windstopper thermals; woolly socks; PHD down socks; PHD Minimus down trousers; old Karrimor down jacket and a fleece hat. Works fine, with the bonus of being able to wander about in it in the evening, or start riding in it in the morning if it's a bit nippy.
Packs small and is warm enough. In winter I add a Buffalo bag and leave the bivi bag at home.
Warm feet are my key to a good night's sleep.

Why is it touring bikes always seem to come under geared?

everyone is leaner than me mate........

but i do sleep hot. so was thinking, silk thermals, down jacket, in a hunka. on a exped mat. may test my theory tonight in the garden so i can come inside if i get too cold.

My experience is that sometime around 4am, you'll wake up freezing. Summer nights in the UK can still feel very cold.

Silk thermals, like this?

I’ve tried a few variations of this in the past and not enjoyed myself that much.
You really need to ask yourself if sleeping well or carrying little is most important to you.
To be comfortable (IME) you need to carry as much clothing as a good sleeping bag would weigh. Muddypete looks to me to confirm that with what he is sleeping in to avoid a sleeping bag. If this is for the Dales Divide my take on it would be to make sure you are getting sleep when you need it, not shivering in a cold bivi bag. I assume you are going to sleep at least twice, 3 or 4 times maybe? That’s a long time if you get it wrong.

There was some itinerant cycling piano tuner I followed for a while who just had PhD down top and bottoms in a bivi, with a mat, and seemed to do fine.

For me if I've had a long ride I'll often have a bit of a chill, maybe low blood sugar or over working and sweating? So I appreciate plenty of layers and insulation as well as a brew and food to warm up.

Gears are never low enough/too low for me either! All my bike have had bigger cassettes fitted even with sub and super compact gears. I loaned a recumbent the other week to try for my wrists, great on the flat or downhill, uphill was a super crawl and I'd never get it up the hill out the village. Saying that it was 1988 triple with a 6 speed cassette and friction shifting

Ton, I'm edging towards this approach too but looking for a decent
Lightweight quilt to marry with it, I struggle with sciatica whilst sleeping
So a mummy bag is too restrictive, anybody any thoughts on one ?
Apologies for the slight thread hijack Ton but I think the 2 approaches
Will work well ?

I tried this once, with thermal leggings, wool socks and hat, a down jacket, and a synthetic silk sleeping bag liner inside a bivvy bag. The wind blew the bag against my legs, and made for a very cold night. I have not repeated the experiment.

I'm interested by what you identify as "in summer".

ton wrote: ↑Fri Apr 23, 2021 7:03 am may test my theory tonight in the garden so i can come inside if i get too cold.

We've been down to -3° / -4° here this last week! Hardly what I'd call summer

I find sleeping bags restrictive (broad shoulders, 100kg) and use a quilt in summer (10°C +) with base layer, socks and hat. In colder conditions I use a half-bag (pied d'elephant) and down jacket with base layer, socks and hat - the colder the likely temp the higher rated the jacket, etc..

I've not tried it but for me I err on the side of comfy sleep. I save weight and bulk with a borah bivi (if banking on no rain and/or there will be enough natural / free shelter) and a lightweight synthetic/down quilt that I got off someone on here (Rich??). Anyhow, drafts and cold spots can bug me so I prefer the penalty for the "luxury".

If it works for you though have at it

On the Cairngorm Loop in 2019 I slept in just my cycle shorts, jersey and a Primaloft jersey inside my SOL bivvy bag and on an insulated mat. It was fine for the three hours or so I stopped until the moonlight woke me up. I did have my quilt with me but was tired enough not to care.

I wouldn't make a habit of it and wouldn't choose to leave the quilt behind.

I'm with Colin - for a few hours shut eye when knackered on a 2 day ride, I'd go for it, but not to be out for 3/4 days or more, especially without a stove. I'm going with 1 season bag plus a light duvet jacket and thermals, which can be worn while riding if needed. It's been frosty every morning up here recently.

In some instances, a quilt will weigh less and pack smaller than a suitable down jacket / thermals combination and generally be much warmer. I've taken a Cumulus 150 down to just above freezing without suffering, which isn't bad for 300g or so ... someone the size of Tony may find it much too small though.