How to increace average speed?
 

This is probably a noob question butwhen I get into a nice paceline I find it hard to keep up. I can do 24mph just fine but when we bump it up 2 mph to 26 I physically cant hold it. I have the endurance from cross country running and I have sprints and hills. I just need to bump up my speed on flats. Are intervals the way to go? If so, how long and how many? 2 min max heart rate 5 min recovery and do that for 30 min? 20 min a little below the max and then recovery then again? Im so lost.

Google is your friend. All intervals are good and are the quickest way to increase power. Some of each. And just hanging on is good interval training. Keep trying. And increasing weekly mileage. If you're under 150 you could step that up. Work on your pedaling dynamics - smooth circles. Try 10 minute climbing repeats at 50 cadence, HR just sub LT. No upper body movement. Do some long intervals at 115+ cadence. Sounds like you're keeping up on hills, but getting dropped on the flat. That could mean you need more strength, which might be helped by weights, though that's probably not the most efficient use of your time if it's limited. If it's not, then gym work is good.

I start swimming in 2 weeks which has a fair amount of weights so that should help. My weekly milage is like 50 at best so that should definatly be stepped up

This man is already cycling so time obviously is not his main concern. Weight training will give you more gains in strength, muscular growth and fat-loss with less a time commitment then cycling or any other aerobic exercise could ever hope to do. So I'm pretty lost on your claim here.
mtb man, I take it you are a swimmer by competition and your training involves weights, yes? Are you doing squats (and for that matter full depth, or at least past parallel squats) as part of your lifting routine? Are you deadlifting? If not, start both ASAP.
Also, just try and keep up with the paceline no matter how killed you are at the end of the ride. If you get dropped by the group, so be it. Just try and hold on longer the next ride.

Uh yeah, just not cycling specific strength. Except possibly for sprinting and track, and even that's not sure, nothing makes you a stronger cyclist than riding. Lots of studies of that out there. Conventional weight training shows no decrease in cycling TT times, whereas cycling intervals show huge decreases. However, for an untrained rider with plenty of time, doing some weight training is not a bad idea, either. This is also my personal experience over 50 years of riding.

What gives up when you can no longer hold 26mph? Does your HR go through the roof and hit max? Or does your legs burn, tighten up and cramp?

Either way, intervals are your friends. Short anaerobic intervals to max-HR and longer aerobic 2x20 tempos will get you there. Do one day of 2x20 tempos and two days of anaerobic intervals a week and you'll bump up that average-speed and will be able to hang with the pack. Be careful of overtraining. If you're already doing the maximum time & mileage that you can, then you'll want to cut back on other things.

I heard that if you learn how to spell "increase", your average speed skyrockets.....

Uh no... weight-training will help with endurance and muscle-fatigue and allow him to go farther at his 24-25mph limit. But it won't help him much with the 26mph. It'll help somewhat, but he needs to do FTP training as well.

Another area the weight-training will help is in the spurts up to 30mph+. With more strength, you can do more of those jumps, do them faster and recover faster. But it still won't help with maintaining the 26mph to stay in the pack.

Practice upping and upping ur cadence like first go at 70% as long as u can and work ur way up to a 100% sprint till ur done thatll get ur legs powerful and help with rhythm which'd increase ur speed

These are very important Q's. First you gotta define whats holdin you back.

and a few other Q's
what gearing do you commonly ride in at 24 mph, and at 26?
what cogs does your cassette have?
are you fallin off after doing a pull? or are you falling off because you can;t hold a wheel?
age? (assumption is you're 'good' on the weight to blubber ratio...)

intervals are always a good thing, but its always better to strike the nail properly than having to get a bigger hammer...
26 is not at the upper realms of group ride performance, so you're not trying to do something which might require a huge concerted effort.
In fact, you may already be at a point where you can do this and just haven;t assembled the right tools to get there.
50 miles a week is definitely holding you back... That would not even be 3 hours at training pace on rolling terrain.

Swimming is a great form of exercise. But swimming gets most of its power from the upper body. So for cycling, it isn't going to help.

In my experience, weight training does not really help cycling much either. Cycling is about being able to put out power (high cadence, low resistance) vs weights which tend to be high resistance very very low cadence.

I think the first thing you need to do is increase your mileage. Most people tend to get most of the exercise on week ends. The more aerobic exercise you can get on a daily or near daily basis the better.

Also intensity is important. Slower rides (recovery rides) are important. But you will not go faster unless you ride faster no matter how many miles you do. What I mean, is you need to do some intense work outs at least some of the time like intervals as many have mentioned above. Since you are trying to "hang on" to a group, I don't think that you should work on the really short intervals. I would work long ones like about 3 minutes each. Those should help you increase aerobic power.

1st thing, take the computer off your bike and if it's wireless, and you have to have the data, put it in your jersey pocket.. The difference between 24 and 26 is very little, you are just psyching yourself out once you hit that 26mph speed..